<human>: She and I dated for nearly three years. During that time she was my first everything, and in October we broke up because we both needed time to mature and experience things outside the relationship. Now we're trying to fix things, but the fact that she had sex with two other guys while we were apart is making me feel incredibly intimidated and inadequate. She's still my first and only everything and I'm predisposed to sensitivity and intense anxiety so this hasn't been easy. I'm looking for advice on how to move past this. 

It's especially frustrating because objectively I don't care. On an impersonal level I'm extremely open minded about such things and I see no reason why this should bother me. But every time I think about it I start shaking and I feel like I'm going to throw up just from the nerves. I feel like I'm losing my mind over something I don't even feel that I should care about, and I desperately need help getting over it.

Can you summarize the given text in a few sentences?
<bot>: had a girlfriend, she was my first everything, we broke up temporarily and now she is much more experienced than I and I need help being okay with it.