How do you trust someone new after infidelity ended your marriage?

You trust someone new the way trust is always built: slowly, from what they do over time, not from what you hope or what you fear. After infidelity, the work is less about trusting faster and more about learning to tell an old alarm apart from what is actually happening in front of you.

That is possible. It just takes a little more attention than it did the first time.

Why does it feel so hard to trust again?

Because what happened to you was a real injury, not a mood.

In a study by Annmarie Cano and K. Daniel O’Leary, women who had recently learned of a husband’s affair, or been told the marriage might end, were 6 times more likely to be diagnosed with major depression than women with similarly rocky marriages who had not. They also reported more anxiety.1 A later review by researchers Warach and Josephs describes the aftermath of infidelity as a kind of attachment injury, with effects on mood, thinking, behavior and even physical health.3

So if your body still braces when a new partner is quiet for a few hours, that is not you being dramatic. It is a nervous system that learned a hard lesson.

There is also a pattern worth knowing about. Kayla Knopp and colleagues followed 484 adults through two relationships. People who had suspected a first partner of cheating were four times more likely to suspect their next partner too.4 The study does not say whether those suspicions were right. It does suggest that suspicion can travel with you from one relationship to the next.

How do you tell an old fear from a real red flag?

It helps to separate four things every time the worry shows up.

• What happened. The facts only. “He said he’d call at eight. It’s nine.”
• The reading. What you think it means. “He’s with someone else.”
• The fear. What it touches in you. “It’s happening again.”
• The next step. What you can actually do. “Text him and ask if tonight still works.”

Say Dana, 48, is three months into dating Chris. He goes quiet on a Saturday afternoon. Her mind jumps straight to her ex-husband’s “golf weekends.” When she writes it out, the facts are thin: one quiet afternoon. The fear is huge. That gap is the old injury talking.

A real red flag usually looks different. It shows up as a pattern you can point to, not a single gap: stories that keep changing, plans that keep vanishing, or anger whenever you ask a simple question. Even then, the pattern tells you something is off. It does not tell you what is going on in their head. The next step is a direct conversation, and if that does not help, a decision about what you will accept.

What does trust actually rest on?

Researchers John Rempel, John Holmes and Mark Zanna described trust in close relationships as having three parts, and a 2025 study by Omar Camanto and Lorne Campbell found the same three:

• Predictability. Do they act in consistent ways you can learn?
• Dependability. Are they honest and reliable when it counts?
• Faith. Do you feel confident they care about you, even about a future no one can see?5

Notice the order. Faith is the last piece, and it rests on the first two. You cannot skip to it, and you should not be asked to. What you can do is give a new person the chance to show predictability and dependability, and then pay attention to what they show you.

Is checking their phone ever okay?

It is common. A 2019 Pew Research Center survey found that about one in three Americans in a relationship had looked through a partner’s phone without them knowing.6 Yet seven in ten Americans said that is rarely or never acceptable.6

The trouble is that checking rarely settles the fear. If you find nothing, the anxiety often says “you didn’t look hard enough.” If you find something ambiguous, it grows. And if your partner finds out, you have broken their trust while trying to protect your own.

A better question is what you need in order to feel secure, and whether you can ask for it out loud. “I’d like us both to be open about who we’re talking to” is a conversation. Secretly reading their messages is not.

How do you avoid making them pay for your ex?

By owning the fear as yours, while still asking for what you need.

Your new partner did not cheat on you. They can, however, be told that you have a history that makes some things land harder. That is fair to share. What is not fair is treating every late reply as a confession, or asking them to prove a negative forever.

Rosie Shrout and Daniel Weigel found that people who had been cheated on and blamed themselves, or kept blaming the partner, tended to struggle more with depression and anxiety.2 That was a study of college students, but the point travels: the story you tell yourself about the betrayal matters. Knowing where the responsibility sits, without letting the betrayal define every new person, is part of healing.

The scripts above are a place to start.

When is it time to get help?

Some wariness after infidelity is normal and fades as safe experiences pile up. But if the fear is constant, if it keeps you from sleeping or working, or if it is wrecking relationships with people who have given you no reason to doubt them, that is a sign to see a licensed therapist. The National Institute of Mental Health notes that when anxiety does not go away, and gets in the way of daily life and relationships, it may be more than ordinary worry.7 That is something a professional can help with, and it is not a verdict on you.

What the research does not tell us

• The depression study was small (50 women) and looked at wives, so it may not reflect everyone’s experience.1
• The serial infidelity study measured suspicion, not whether suspicions were accurate.4
• The appraisal study used college students, not divorced adults.2
• Trust research describes how trust usually grows. It cannot tell you whether a particular person is trustworthy.

What to do this week

• Pick your answer above and try its next step once.
• Keep a facts list. Each time the worry rises, write what happened, the reading, the fear and the next step.
• Choose one need you can ask for out loud, and pick a script to adapt.
• Notice one thing they did that was predictable or reliable this week, and let it count.
• If the fear is running your days, book a session with a licensed therapist.