<human>: My girlfriend and I have been together for a bit more than 7 years - since high school. About three months ago I started discussing marriage with her. I wish I never had. After a few conversations she started freaking out, "it's too much", "I'm just not ready." Then she said she wanted to take a break. I was very reluctant but I knew that if I smothered her she would just push me further away. So I agreed, with one condition, that she not have sex with anyone else. She agreed. She took a suitcase of stuff from our apartment about 2 months ago, stayed with a friend and I did my best not to contact her.

Earlier this week she said that she's sure and that she wants to get back together - she's sure that she wants to be with me now. The next day she told me she slept with someone else. I knew she was going to do it. I just wished she wouldn't. I believe 100% that this is an isolated incident and I know that I could trust her if we got back together. 

The problem is that I don't know how to deal with her having slept with someone else. She and I had only ever been with each other, now that's gone. She is an amazing girl and I know I would regret it if I didn't take her back. But how do I get over this? The thought of another guy being inside of her makes me sick. Right now, I don't want her to touch me, I don't want to touch her. I just don't know what to do. Will this sick feeling pass? Advice is appreciated.

Can you condense the text into three sentences or less?
<bot>: My [M23] girlfriend [F23] (7 years) slept with someone else while we were on a break even though we agreed not to. I don't know how to deal with this.