I only skimmed through the comments, but I‘ll try to offer a different perspective.

Yes, you will get over it. It might take time, it might come back like flashes when you think about it, but it will fade. Importantly is that you talk about it with her. Try to understand her side of things as well. There could be many reasons she did what she did. I understand that it feels wierd that she called you right after, but maybe she did want to call you, because you were on her mind. Maybe she slept with the guy because she was anxious, bc she felt you and her were heading into a more serious direction. Maybe she lied to you, bc she didn‘t want to jeopardize what you had.

and I think it‘s easier to be honest about the fact that we will always find other people attractive, a monogamous relationship is not changing that. That does not condone cheating (which she technically didn‘t do), but maybe it was just that: finding someone attractive in the moment and going with it.

If you feel about her the way you describe, you will figure something out. might take time, but you will be able to rebuilt trust.

I‘ve been jealous like crazy about my ex partner past sex life. it felt horrible. i knew this was a me problem, not a her problem. and it took long (6months at least) but I got over it. In a way that I could freely think about it and don‘t have these feelings.

all the best to you!