Relationship anxiety/ROCD?

I feel like my brain is ruining a healthy relationship.

I (24F) have been with my partner (28M) for about a year. We have a loving relationship, live together, and I genuinely see him as the person I want to spend my life with.

Our relationship had a difficult beginning, and we both made mistakes that affected trust. We’ve talked through them, forgiven each other, and both chose to move forward. Rationally, I believe we’ve built a healthy relationship since then.

The problem is that my brain doesn’t seem to believe it.
A few weeks ago, something happened that triggered my anxiety. My partner interacted with a female friend in a way that made me uncomfortable, and he handled part of the situation poorly. We talked about it, he apologized, took responsibility, reassured me there was nothing going on, and has been incredibly patient and supportive ever since.

The issue is that I can’t let it go.

I replay everything over and over. I analyze every interaction, constantly wonder if he’s secretly losing feelings for me, and end up asking for reassurance far more than I’d like. I’ll ask things like, “Do you still love me?”, “Are you happy with me?”, or “Are you sure you’re not getting bored of me?”

He always reassures me, but the relief only lasts a little while before the anxiety comes back. It’s like my brain immediately finds another reason to doubt everything.
The confusing part is that logically, I trust him and I do believe him. I don’t actually think he’s cheating or planning to leave me. He wasn’t, he isn’t and he isn’t going to. My emotional brain sometimes just refuses to accept what my rational brain already knows.

I also carry a lot of guilt about mistakes I made earlier in our relationship, and sometimes I wonder if that’s feeding this fear that I’ll eventually lose him.

This cycle is exhausting. I’ve had anxiety attacks, nightmares, intrusive thoughts, and periods where I can’t stop crying. I don’t want to keep putting the burden on him to calm my anxiety because I know that’s unfair, and I don’t want my fears to become the thing that damages our relationship.

Has anyone else experienced something similar? Does this sound like relationship anxiety or ROCD? If you’ve managed to get better, what actually helped? Did therapy, ERP, medication, books, or specific techniques make a difference?

I’m looking for advice on how to stop letting anxiety control it.