Hi all, this is a long one, but I'd really appreciate any insights you have.
My girlfriend and I have been dating about a year or so. She has been in many long-term relationships before this one, I have not been in very many (she's 25, I'm 24). There have been 3 instances, two of them recently, in which her trust issues/insecurities from past relationships were triggered. She has had one boyfriend cheat on her, and the last one basically lied to her the entire time they were together. I should note that she was at first wary of a relationship with me because she had gotten out of the last one (4 years) about 6 months before we started hanging out and dating. She did tell me about her trust issues/insecurities going into the relationship and we talked about them more after the first of the 3 incidents.
1st incident happened last November. We went back to my college town to visit my friends, some of whom are women. Everyone was drinking, one of my platonic female friends who I hadn't seen in awhile was going to leave early, another one of my female friends jumped on the one who was leaving's leg and told me to get on to her other leg. I did, not even thinking that it would make my GF jealous. My GF was watching and stormed out afterwards. We almost broke up that night, and she said I had lost a lot of trust with her. I didn't want to end the relationship so I started trying to be more vigilant about boundaries. We talked about boundaries after that, something that we hadn't done before, and I have tried to be very conscious about physical things that would make her uncomfortable.
2nd incident happened the day of our anniversary (this was especially bad). We went on a hike, which we do a lot, and somehow got to talking about religion. I mentioned that one of my previous GF's was a Baptist, and she started asking questions about her. I replied truthfully as it's my policy to be completely honest, and one answer where she questioned as to whether or not I had gone to see this girl when the girl had asked me to come over (the girl had just gotten out of boot camp and wanted me to have sex with her) and I told her I did go see her, but we didn't have sex. We were able to work it out eventually and agreed that we wouldn't talk about past relationships anymore (she brings up her last ex a lot and that irks me. she hasn't done it much since though).
Last incident happened just a few hours ago, again with a platonic female friend from college (different college and friend group than the first incident). We were out at a bar signing karaoke, which the platonic friend and I have done before. The friend and I sang two songs together, Livin' On a Prayer and The Bad Touch (Discovery Channel). The second song is pretty sexual in nature, but since I've been such good friends with my platonic friend for a long time (she is like a sister to me) I didn't think much of it, though I had an intuition that my GF would be uncomfortable about it, but I didn't ask her about it. I regret not listening to myself. We dropped my platonic friend and her boyfriend at their apartment after we were done, and then my GF exploded, saying that she was very uncomfortable that I had done that, that she didn't want me touching her, etc. It was a very long car ride home, during which I stayed pretty silent while she pretty much made me feel like shit for singing the songs.
After we got home we did talk a little bit, but she is still angry with me. How can I help her work through these issues? I'm worried that I will do something without realizing it and trigger her again. I want to school myself to be more aware of how she is feeling, but since I've been friends with these other women for so long it's very natural for me to do stuff I did with them before I was in a relationship, and I forget to ask myself how my GF is feeling about it. To me it's just a female friend who I have no sexual interest in. I'm worried I may have to give up my female friends, and I don't want to do that. I really do love my GF a lot, and I'm disappointed that I didn't listen to that voice in my head that told me not to sing the songs tonight...would appreciate any and all advice.