Would love some objective advice

Before I go on, I'm totally aware that I have problems. I am in therapy and have been for along time, I constantly try to get better in this area and DO get better, but it's a very slow process.

So here's my story.

I met my girlfriend a year ago and we fell in love pretty hard. The first 4 months we weren't "together" we were in that stage of "Oh i don't want anything serious". Basically we were both being super insecure and pushing each other away. During that time we both slept with other people. When we finally got together things were perfect, a dream. About a month in we bumped into her ex and i asked the question "when was the last time you saw him" she replied "ages maybe a year". A few months later we finally decided to have the conversation "so, did you sleep with anyone while we weren't "official"". I was immediately honest and told her everything, she didn't like it but understood that I had done nothing wrong. She then told me that she'd slept with her ex once. See a few sentences before. She'd lied originally. She admitted she had panicked and lied before, but this really set me off and basically ruined our relationship. I got super paranoid and jealous and insecure I couldn't get a handle on it. We had both done nothing wrong in our act of having causal sex whilst single, but the lie sent me crazy.

We ended up slitting up 3 months ago, she broke it off with me saying she couldn't handle it anymore, we had totally spiralled out of control. I understood and respected her decision. I was devastated - I'd been through a lot of break ups but never one like this, boo hoo etc. Anyway. We remained in contact and carried on sleeping together. I'd asked for her back a few times during this period but she said no each time. Eventually I gave up and got on with my life. She eventually came back to me. "I never stopped loving you, I'm an idiot, I was scared, I'm so sorry, lets get back together" and back together we got. Things are great again.

But

I'm struggling again. Who did she sleep with the 2 months while we were broken up? She promised she didn't, but she also said in conversation that she wouldn't tell me if anything meaningless happened with anyone because it would make me spiral into jealousy and paranoia. Which makes total sense, but also kills me. I know a lot of people will say, "just leave it then, she loves you that's all that matters, ignorance is bliss" but this isn't that simple. I'm sick with paranoia, jealousy and curiosity. I've raised it with my therapist and I'm doing the same CBT techniques I've been doing for years.

Is this as much of a mess as I think it is? We're super happy together, and I hide these thoughts as best I can because they're my problem, not hers. I trust that she isn't cheating and hasn't cheated (which is a first for me, this is how I ruined all my other relationships, constant paranoia - which shows THERAPY WORKS, YAY!) but the question of "what did she do when we were split up?!?!" I just CANNOT seem to kill. I can't ask her over and over again, that's not fair. Any two cents would be hugely appreciated.

Lots of love and thanks.

That's excellent. here is more good news: Psychotherapy can make you richer - especially if you are a man

I've raised it with my therapist and I'm doing the same CBT techniques I've been doing for years.