He wants exclusivity but still talks to his ex: what to say

He used two different ideas in one message. Exclusive is a commitment about you. Still talking to my ex is a fact about his current life, and he put the fact in the same breath as the commitment on purpose or by accident. The word sometimes matters too. It tells you the contact is irregular, which usually means it's not a daily thread, but it also means he's not sure how to describe it, which is itself information.

Pay attention to what he chose to disclose. People who are only hedging often leave out details. He told you about the ex unprompted and framed it as nothing huge. That reads as a man who wants credit for candor and hopes you'll take the rest on faith. It doesn't tell you whether the contact is platonic, whether it started recently, or whether she's the one initiating. You don't have to know those things to decide what you need.

Most of the emotional weight in this situation comes from not knowing where the line is. Is texting fine. Is meeting for coffee fine. Is a late-night call fine. Each of those means something different to different people, and he's probably guessing at yours. Your reply can close that gap by naming the one or two things that would make exclusivity feel fake to you.

You don't need a full policy. Pick the things that matter most and say them plainly: that you're not comfortable with him seeing her alone, or that texting her late at night would bother you, or that you need him to tell you if that changes. Specific limits are easier for him to respect than vague feelings, and they give you something concrete to check later instead of a feeling you keep re-measuring.

A reply that answers his message is not the same as a decision about the relationship. If you've been exclusive with someone for two weeks and this comes up, you can say what you need and then watch what he does with it over the next week or so. Does he adjust without being asked twice. Does he bring her up again unprompted. Does he get defensive when you name a limit. Those responses tell you more than any reassurance he gives in the moment.

If he hears your limit and goes quiet for days, or says you're being controlling for wanting it, you've learned how he handles your needs when they cost him something. That's the point to step back. If he takes the limit without fuss and keeps being warm and clear, you can keep going and check in again in a few weeks. Set a date in your own head so you don't end up reopening the question every time he's slow to reply.