My girlfriend and I have been dating since college (1 yr close 2 yrs long distance and now she moved to my city to be closer to me). At dinner she said something weird about a guy hitting on her while she spent the weekend at a friends house. She left her gmail account open on my computer and I read chats about how she thought this guy "is a cutie", her skinny dipping with a group of people (including the guy who hit on her), and told her friend that she slept in bed with the guy who was hitting on her, but that nothing happened (Her friend likes the guy who my girlfriend slept in bed with so I am suspicious that she would lie to her friend as well).
I confronted her about this a few nights ago, and she denied it, and cried and swore at me and called me a pyschopath. It was not until I showed her the chats that she admitted to skinny dipping and sleeping in a room in bed with just him. At this point I thought she was hiding more, and I pressed her. She told me that if she told me the truth that I would "call her a whore and break up with her." I couldn't get her to say anything else and fell asleep.
Yesterday I refused to let her lie to me. I told her that I would break up with her unless she told me the truth. She maintained her innocence but I stayed firm and told her that I did not believe her. She said that I was being irrational and that this is why she wasn't comfortable telling me the truth about sleeping in bed with him. When I made it clear that I was leaving her (after hours of asking), she said wait, are we going to be together a month from now, and I said that we would be if she told me the truth. I asked her if she made out with him, and she said yes, I asked if she had sex with him, and she said yes. She also admitted to making out with another guy while dancing at a bar.
I went over to her house and she apologized and apologized and said that she made a mistake and she was very sorry and cried for some time. She wanted to know if we were breaking up. She is my best friend, and I did not want to break up with her. In the interest of being honest I told her that I did not want to break up with her and that I still really loved her. After talking for awhile, my jealousy got the better of me and I began asking for details and got mad and told her that I don't think we should stay together because neither of us would be happy. Eventually, I said we should take a break and began walking towards the door but didn't have the heart to leave and sat back down. I said that I would stay with her but things would be rough.
This is when she said, ok don't get mad and break up with me, but I didn't have sex with him. She said that I had put her into an impossible corner and that I was going to break up with her unless she told me that she had sex with him. I can see that I wasn't taking no for an answer and she really did have to say that she had done something with him. I didn't necessarily think they had sex, but I was pressing her for answers very hard. She does not deny making out with the guy at the bar.
Today she is still very sad and seems to be trying to make up for things. I don't know what to do and wonder if I should 1. press her again to find out if she was lying about lying, 2. stay with her and try to forget, or 3. break up with her and try to move on. I want to make things work but I am worried about the poison that will be in our relationship if I am always thinking in the back of my mind that she was lying to me.
Additionally, I have not been a model boyfriend. I have never cheated on her, but long distance was very rough and I ignored her and didn't visit her as often as I could have/should have. I wouldn't think that it was my fault if she cheated, but I can understand why she looked for attention in other places. Things just won't work as they stand now and I need to figure out how to learn the truth.