<human>: Can you summarize the given text in a few sentences?

Hi everyone

As the title suggests I am the recipient of some bad news. I'm still in shock! She hardly ever drinks (once every few months) and things were going swimmingly.. it's all so cliched really, things were going perfectly, then suddenly disaster. She called me up the following morning and said she doesn't remember anything, got blackout drunk, woke up the next morning having clearly had sex with the person next to her. If this is true she could not have given consent, which concerns me. On a more selfish note the trust has now been broken, as we had made the choice together to be monogamous.

I'm posting because I want to hear what other people have done in these situations, or if you have any words of advice or comfort. I've had over 10 relationships and have cheated, and been cheated upon and I haven't been able to make things work after, so I feel like it's best to just move on, despite the fact that she's the first girlfriend I've wanted to settle down permanently with, and she has said the same of me. Bizarrely I feel like this is some sort of karma, like I still have unresolved fidelity issues which are resurfacing in this way.
<bot>: girlfriend cheated on me, begs me for forgiveness, I don't think I can but want to hear input from you guys