So my girlfriend and I decided to go on a break about 3 months ago, but we were still hanging out and hooking up during that time. We both enjoyed being with each other but also having the freedom to be with other people. Two weeks ago, we both moved into the same house (a giant house that is being shared by about 30 college students), and we began to act like a couple again. Neither of us hooked up with anyone else, we spent pretty much every second together, and we slept together every night. Then I went home to the East Coast for a week to see my family. In the middle of the week my ex/non/semi girlfriend called me saying that she was unhappy and that she needed to know that we were together now, otherwise she was going to replace me with the wrong person simply to fill the empty void inside of her. I wanted to get back together with her, so I said ok, although I had had no idea that she was unhappy and had thought we had been happily rekindling our relationship before I left. THEN, when I got back, my girlfriend told me that she had had sex with some football player 2 days after I'd left for Connecticut. I flipped out. Now I'm not sure I want to get back together with her -- how could she have had sex with someone 2 days after I left but still wanted to get back together with me? Am I overreacting? Am I failing to see her side?