Probably the hardest lesson I've had to learn so far in my life, and something I will never, ever do again. Without getting into too much specifics. I've been a partner in our company for quite some time now. We hired my now ex on and things started happening between us. She had a boyfriend whom she broke up with because she was either sick of him, or liked me that much, or possibly a little bit of both. I noticed how she jumped from him to me. I put it in the back of my mind as that is a big part of someone's character. I didn't like it, but I accepted it. "hey I got the girl so F it". Fast forward almost 2 years later and we hit a rough patch. She breaks it off with me and we still had to work together, and I was MISERABLE. I met someone else whom I enjoyed spending time with and she caught wind of this. Guess who came back. I made the STUPIDEST mistake and took her back. Burned the bridge with the new girl whom I was having a lot of fun with, and moved forward with my no longer ex. Seven weeks later she starts acting weird and I tell her we need to talk. I told her I think we needed to take another break, because I knew what was coming and I wanted to save face this time. I see her flirting with one of our affiliates on her facebook and instantly realize there was something there, and had been something there between them for a couple weeks. I freak out on her and tell her how much of a terrible person she is for not just "manning up" and breaking things off with me if she knew she didnt want me anymore. She couldnt even man up and say that she liked this dude, even though I knew she did because I saw it with my own eyes. She claimed it was nothing, and now 1.5 months later they are full on dating. Time proved what I knew. The thing that hurts so much is that she had to be a little freaking girl about it the first time, and come running back as soon as she saw I was hitting it off with another, only to turn around and dump me as soon as SHE found someone else she thought was better than me. NOW I get to see her every day and have her pretend that we are best freaking friends, and I have to put on a happy face because I look like the ass if I don't. THIS IS THE WORST and I dont know what to do because I honestly loved this girl and wanted to marry her. She clearly just jumps from guy to guy to guy. I dont know whats up with that.