If you and your partner used to say “I love you” every time you hung up the phone, and now you mostly just say “bye, love you” in passing — or skip it some days entirely — that shift is not automatically a warning sign. A 13-year study of 87 middle-aged and older couples married between 15 and 35 years found that spouses actually showed more tenderness and more humor toward each other as the marriage went on, not less, according to research from the University of California, Berkeley’s Psychophysiology Laboratory reported by UC Berkeley News. What changes with time, the research suggests, often isn’t how much love is there. It’s how loudly, and how often, a couple feels the need to say so out loud.
Long, Happy Marriages Got More Affectionate, Not Less
Psychologist Robert Levenson and colleagues Alice Verstaen, Sandy Lwi, and Claudia Haase videotaped married couples having 15-minute conversations about both shared positive experiences and points of conflict, then coded the footage for emotional expressions — anger, contempt, affection, and humor — at multiple points across 13 years, as part of a larger 25-year study following more than 150 long-term marriages, according to UC Berkeley News. Positive behaviors increased with age while defensiveness and criticism declined, a pattern that held regardless of gender. The one nuance: wives grew more emotionally expressive overall but also somewhat more domineering and, by some measures, less overtly affectionate — a sign that the shift isn’t a straight line toward more of everything, but a broader move toward a couple’s own steadier emotional register.
The Science of Why “I Love You” Can Stop Landing the Same Way
Separately, basic research on emotion offers a clue about why the phrase itself can lose some of its charge even when the feeling behind it hasn’t. A 2025 study by Elizabeth Yartsev, Oliver John, and Özlem Ayduk at UC Berkeley, published in Personality and Social Psychology Bulletin, tracked how people’s emotional reactions changed with repeated exposure to the same stimulus and found that positive reactions fade faster than negative ones — people habituate to good things more quickly than to bad things, even when the good thing hasn’t gotten any less true or less intense on its own terms. The study wasn’t about relationships specifically, but the underlying mechanism, known as affective habituation, is the same one that can make a phrase repeated dozens of times a week hit your nervous system a little less each time, independent of whether you mean it just as much as the first time you said it.
Put those two strands of research together and a familiar relationship pattern starts to make more sense. A phrase said less often isn’t necessarily a phrase that’s become less true — sometimes it’s simply a couple who no longer needs to use it as a check-in, because the security it used to signal is already assumed between them. The Berkeley marriage data suggests that what actually tends to erode over decades together is conflict, not affection; couples in that study grew warmer with each other even as some of the routine verbal habits of new relationships fell away or changed shape.
What Would Actually Be a Warning Sign
None of this is an argument that words never matter. Researchers who study long-term couples generally agree that some form of ongoing verbal and physical affection matters for relationship health over time. The distinction worth paying attention to is between a phrase that’s simply said less often and a broader pattern of disengagement — less eye contact, less curiosity about your day, less physical affection in general, or a sense that your partner has stopped noticing you at all. Frequency of one specific phrase, on its own, wasn’t what predicted relationship quality in the research reviewed here. What predicted it was the broader emotional climate of the relationship — and on that measure, the couples who stayed together longest tended to be getting warmer with each other, not colder, even as their day-to-day habits changed around them.
So if the words have gotten quieter in your relationship, the more useful thing to check isn’t how many times a week you’re saying them. It’s whether everything else that used to come with those words — the attention, the affection, the sense of being on the same team — is still there, just expressed differently now than it was at the beginning.
