<human>: Can you provide a brief rundown of the text in within 3 sentences?

So, I dated this girl for 2 years. She was the first girl I've dated long-term. We fought quite a bit. I didn't live up to all her unrealistic expectations and I had trouble dealing with her emotional issues (depression, bipolar disorder). We broke up about 8 months ago, but since neither of us have many friends, we hung out nearly as much as we did while we were in a relationship. We even traveled to Europe together. 

During this time, she started medication to help with her bipolar disorder and we fought a lot less. I also browsed dating sites and went on a couple dates. Meeting other girls proved how special my ex really was. But, by the time I realized this, she met a guy through her friend. She didn't think we were going to get back together, and I gave her no indication I was considering it. 

Anyway, after she started hanging out with him all the time instead of me, it felt like we had finally broken up (instead of breaking up and then spending lots of time together like we did before). It was really painful and lonely. I thought about all the stuff I missed about her. I actually cried for a couple days and decided to tell her. My feelings didn't seem to register with her. She had already moved on. But a couple days later, she came back crying and saying she feels the same way. The thing is, during those two days, she had sex with the new guy for the first time. Her number of partners was already much higher than mine and it caused me a lot of discomfort. Now, she just added one more. So, if we were to get back together, knowing that some other guy slept with her since we first started dating, I think it would make me feel insecure for the rest of the relationship.

I'm not blaming her in any way. We were broken up and she can do what she wants. I'm just upset at myself for breaking up with her in the first place. Now, I have another reason to be insecure.
<bot>: Broke up with girlfriend, but remained friends. She slept with a guy while we were broken up. Now, we're thinking about getting back together and I feel like knowing that she slept with another guy would eat away at me.