Why we built this, and what the research actually says.

To feel loved is good. To feel understood and accepted is deeper. That is the whole of what we are trying to help with.

Every couple carries a set of questions neither of them has asked. Early on, because it feels too soon. Later, because it feels too late to start.

What neither of you knows is not who the other is; it is what the other would say yes to, if asked plainly and in private.

Not because either is hiding something. Because asking is awkward, because the answer might disappoint, and because a question asked out loud puts the other on the spot. So the question is not asked, and a small unknown becomes a permanent one.

Just Us asks it instead. Each of you answers alone, without knowing what the other answered. The app only ever shows you the things you both said yes to. Everything else stays where it was: private, and unsaid.

Four things happen, in order, and only the first is about questions. You explore what is there. You listen without putting anyone under pressure. You understand what the other actually meant rather than what you had assumed. And you accept what you find, including the parts you do not share.

Two adults in a relationship. That is the whole of it.

Both of you need to be eighteen or over. That is a rule, not a caution: Just Us asks about desire, and it is built for adults only.

Beyond that, nothing about you needs to fit a shape. The questions do not assume your genders, or who takes which part, or whether you are married, or whether you live under the same roof, or whether you have children, or how long you have been together. Every person sees the same cards in the same words, because we have no reason to write a different product for anyone.

One thing it is not: Just Us is not a way to meet anyone, and not a way to choose between people. It only ever works with two people who are already together, and it never compares, ranks or scores either of you.

Both, for the same reason and with a different payoff.

A new couple is still mapping the other person, and every question asked out loud carries a risk of landing badly. Just Us does the mapping without that risk: you find the overlap quickly, and the things that did not overlap are never mentioned. If you have been together for years, the overlap is still there; it has simply gone unexamined, because the two of you settled into what you assume about each other and stopped checking.

In both cases the product does the same thing: it finds common ground neither of you suspected. Knowing someone and knowing what they currently want are different things, and the second one keeps changing.

There is also a measured reason. In a study that asked both members of forty-eight couples to keep a private daily diary for three weeks, the two partners had a sexual thought about each other on the same day in only about a third of the days. Two out of three days, one of them was thinking about the other, and the other had no idea.

That gap is not a problem to be fixed by trying harder. It is simply what happens when two people's inner lives run on separate clocks. An instrument that lines them up is doing something conversation alone does not reliably do.

Birnbaum, Kanat-Maymon, Mizrahi, Recanati & Orr (2019), Study 3.

Because a question asked face to face is never only a question. It arrives with a face attached, and the answer has to manage that face as well as be true.

Answering alone removes that. You are not declining your partner, you are answering a card. And because the app shows nothing unless you both said yes, saying no has no cost: your partner never learns that a question was even asked, let alone how you answered it.

This is the single design decision everything else follows from. The product is built so that the only thing that can ever be revealed is something you both already wanted revealed.

There is real research, and we want to be precise about how much of it applies.

Sexual fantasy has been studied for fifty years, mostly as a question of content: what do people imagine, and how often. That literature is large and it is not what we are built on. The part we rely on is much smaller and much more recent: the handful of studies that ask what fantasising and sharing do to a relationship, rather than what they consist of.

Four findings carry the product. Each is named below, with its source, and each is stated no more strongly than the study allows.

In 2019 a team at Reichman University published four studies in Personality and Social Psychology Bulletin. Two were experiments; two were daily diaries kept by both members of couples, for twenty-one and forty-two consecutive days.

People asked to fantasise about their own partner subsequently reported more desire for that partner, and more willingness to do something that would make them happy, than people asked to fantasise about someone else. The effects were moderate in size and held up in a second experiment with control conditions.

The finding that matters most is from the diaries. On a day when one partner had a sexual thought about the other, the other one independently reported receiving more warmth and attention that day. Neither knew what the other had written. So this is not a mood people report about themselves. It is something the other person can see.

Birnbaum et al. (2019), Studies 1 to 4. The experimental effects were d = 0.53 for desire and d = 0.57 for relationship-promoting behaviour.

A 2023 Italian study of 1,773 adults measured five separate things about people's fantasy life: how often they have fantasies, how normal they think they are, how important they are, what negative feelings they bring, and how much they share and act on them with a regular partner.

Only the last one was strongly related to sexual satisfaction. How often people fantasised barely mattered at all.

In the same study, the average level of sharing was low: close to "rarely" on the scale used. And it was the one measure in the whole questionnaire that people did not appear to embellish, which matters when the subject is this private.

This is the clearest statement we have found of what Just Us is for. Not more imagination. Less of it kept to oneself.

Nimbi et al. (2023), Sexual Desire and Erotic Fantasies Questionnaire, Part 2.

In 2015 a Canadian team asked 1,516 adults from the general population to rate fifty-five different sexual fantasies, and then to describe their own favourite in their own words.

Of the fifty-five themes, only two were statistically rare. Nine more were uncommon. Thirty were shared by more than half the sample, and five by more than four people in five.

The authors' conclusion is worth quoting almost in full: care should be taken before calling a fantasy unusual, let alone deviant, and the focus should be on the effect of a fantasy rather than its content.

We took that literally. Just Us never ranks anyone, never tells you that something is normal or abnormal, and never interprets what an answer says about you. It reports one fact and no others: that you and your partner both said yes to the same thing.

Joyal, Cossette & Lapierre (2015), The Journal of Sexual Medicine.

This is the result that ties the rest together, and it is the one we found last.

Relationship research has a name for the thing a good couple gives you: perceived partner responsiveness, defined as how far you experience the other person’s responses as accepting, understanding, validating and caring. It is measured, not a metaphor.

In 2016 a team including the same lead author as the studies above ran three studies on whether that feeling has anything to do with wanting someone. In the first, people believed they were talking online with their partner; in fact they were talking to a stranger trained to be either responsive or unresponsive. In the second, couples talked face to face and independent judges scored what they saw.

So being understood and being wanted are not two separate goods that a couple has to trade off. In the measurements, one produces the other. That is why this page talks about listening and acceptance rather than about technique.

Birnbaum, Reis, Mizrahi, Kanat-Maymon, Sass & Granovski-Milner (2016), three studies including an experiment.

It is well documented, and the usual explanation is not that people stop caring. It is that desire is fed by novelty and by not-yet-knowing, and a long relationship steadily removes both. That is not a fault in the couple. It is the ordinary cost of becoming familiar to each other.

Which suggests something specific about what would help: not more effort, but restored uncertainty. A question whose answer you genuinely cannot predict brings back, for a moment, the condition that desire runs on.

That is the mechanism Just Us is built around, and it is also why the app shows you your partner's answer only when it matches your own. The interesting part is not the information. It is the moment before you get it.

As set out in the introduction to Birnbaum et al. (2019), drawing on Birnbaum & Finkel (2015).

Much less than the stereotype claims, on the measures that concern us.

Across recent studies, men and women did not differ significantly in how much they share fantasies with a partner, in how normal they consider having them, in how important they are, or in the negative feelings they bring. One 2014 study that had people write freely rather than tick boxes found no gender difference in explicit content or in affectionate content either, and noted that the difference found by earlier questionnaire studies may have been partly produced by the questionnaires.

This is why every person using Just Us sees exactly the same questions, in the same words, in the same order, whoever they are and whatever the shape of their couple. We have no evidence that would justify writing a different product for each partner, and some evidence that doing so would be inventing a difference rather than serving one.

Nimbi et al. (2023); Nese et al. (2021), n = 3,136; Goldey, Avery & van Anders (2014).

This is the honest gap at the centre of our reasoning, and it is worth being plain about it.

Birnbaum and colleagues asked people to imagine something privately, and then measured what happened. They did not ask anyone to tell their partner. So strictly speaking, their result supports the value of the imagining; it does not, on its own, prove that saying it out loud adds anything.

The authors themselves raise the reverse possibility: their beneficial effects may “reflect disclosures of fantasies or acting on them rather than imagination” alone. That is a reason to think disclosure matters, not a demonstration that it does.

What we have on the sharing side comes from a different and weaker design. Nimbi and colleagues asked about sharing and about relationship satisfaction at a single point in time, and found the two travel together. That is a correlation in a questionnaire, not an experiment.

So the accurate statement is this: fantasising about your partner has been shown experimentally to change behaviour; sharing has been shown only to correlate with satisfaction. We built a product around sharing because the two findings point the same way, not because anyone has run the experiment that would settle it.

Birnbaum et al. (2019), general discussion; Nimbi et al. (2023), SDEF2.

When a questionnaire shows that couples who share fantasies are more satisfied, three explanations fit the same numbers equally well: sharing improves the relationship; a good relationship makes sharing feel safe; or something else, such as general ease with talking, produces both.

Nothing in the sharing literature separates these three. The studies are cross-sectional: everyone answered everything on the same day. The experiments that do establish cause, in Birnbaum's Studies 1 and 2, are about private fantasy, not about sharing.

We therefore do not claim that Just Us will improve your relationship. We claim it will tell you something you did not know, which is a smaller and more defensible promise.

In the diary studies, fantasising about your partner predicted what you did for that partner that same evening. The statistical model even controls for the previous day's behaviour, precisely so that the effect cannot be a leftover from yesterday.

No analysis in that paper shows that today's fantasy predicts tomorrow. So the demonstrated effect is a short one. Anyone telling you that an evening of honest questions will change the next six months is going beyond what was measured.

Birnbaum et al. (2019), Studies 3 and 4: daily diaries kept by 48 and 100 couples.

We would rather say this ourselves than have someone find it.

A 2020 study of 303 people in long-term cohabiting relationships looked at what happens when couples talk about sex. The answer was not a simple yes. Talk about the other person’s pleasure reduced distress when the partner was experienced as responsive, and increased it when the partner was not. The same conversation helped or hurt depending on how it was received.

That is a real limit on what a tool like this can promise. Just Us can make the conversation easier to start; it cannot make the other person listen well once it has started. In a couple where one of the two does not feel heard, opening the subject may not help, and might not be the place to begin.

It is also why acceptance is one of the four words this product is built on rather than a nice sentiment at the end. It is the condition under which the rest works.

Merwin & Rosen (2020), n = 303.

This is the limit we find most uncomfortable, and it does not fall where people expect.

• Birnbaum: Israeli couples, together around three years on average.
• Nimbi: 1,773 Italian adults, mean age 29.
• Nese: 3,136 Italian young adults; the study accepted nobody over 25.
• Joyal: 1,516 adults recruited online in Quebec.
• Goldey: 48 participants at a single American university.

Young, Western, mostly recruited online or on campus, and above all new. So if you are two or three years in, this evidence is about people in your situation, and we are not extrapolating at all.

It is the other direction that is the assumption. We found exactly one study of couples well past the early stage, and it was published in 1980. For a couple of fifteen or twenty years, we are extending findings from newer relationships to settled ones, and nobody has checked whether they carry.

No, and the distinction is not a disclaimer; it is a design constraint.

Therapy interprets. It takes what you said and tells you what it means about you. Just Us does none of that. It never scores you, never profiles you, never tells you what an answer reveals, and never compares you to anyone. It asks; you answer; it shows you where two answers agree. What that agreement means is yours to work out, out loud, without us in the room.

If something you find here is painful rather than interesting, that is a conversation for a professional, not for an app.

Just Us is for adults: both partners must be eighteen or over.

We do, and then couples do.

The starting catalogue was written by hand, card by card, and each card is graded on how exposing it is to answer honestly. The app opens well below your level and moves up only as far as your answers allow; a single refusal lowers the ceiling for the rest of that theme, and it stays lowered.

After that, the questions that matter most are the ones you write yourselves, because nobody knows what is unasked between you better than the two of you do.

They belong to the two of you, together, and they are built to be worthless on their own.

An answer is stored against the pair, not against a person. It cannot be carried into another relationship, exported as a profile, or read back as a description of you. If the pair ends, the answers end with it; there is no residue to follow anyone around.

An answer only ever becomes visible when the other answer matches it. Everything else stays where you put it.

See also our privacy notice.