My ex and I were together for over two years and she broke up with me almost 6 months ago. I am still very upset about it and stuck trying to make sense of her erratic behavior. I know I should just move on, but I keep wondering if she was borderline.

When we first started dating she was immediately all in- she spent $700 on concert tickets and suggested I fly across the country to meet her parents within the first two weeks of meeting her. When I said I would like to take things more slowly, she suddenly just wanted to date casually and strung me along for almost 6 months, fluctuating between being very interested and pulling away. Several times we almost ended things which said was because she was not over her ex, but she kept pulling me back in. The more interested I got the less interested she was in having a committed relationship and the more interested in just "dating". Eventually we did get into a serious relationship and I moved in. I began to notice that she drank really heavily, would often go back on things she said/change her mind and would refuse to acknowledge it or act like it wasn't a big deal, etc. About a year into the relationship, she said she felt depressed and missed home and wanted to move back when the lease was up (which wasn't for another 10 months). Mind you, we had met almost immediately after she had moved to my area, and in a year she had not made any friends nor attempted to make friends. When I suggested she do so she said she had tried before we met (I pressed her on this, because she had once told me that the night we met was the first time she'd been out in the city....she responded by saying she had been to the movies once which seems like a ridiculous answer, because who makes friends at the movies?). Anyways, after she mentioned moving, the next 4-5 months were torture...we broke up several times, she treated me really badly and like I basically didn't matter at all, but once and awhile she would be all over me. I went home with her for Christmas and on Christmas Eve we sat in a grocery store parking lot arguing because she basically said she didn't really want to be with me anymore. I was really upset and taking about flying home, and eventually she said she refused to talk about it anymore. We went into the store, and she was hanging all over me. It was just really bizarre.

About 4 months before the lease is up, she says she's definitely moving and does not want me to come with her. I accept this but we are still living together and dating, although I also begin to date other people (which she knew about). Suddenly, she tells me she feels like she's falling in love with me for the first time, is so sorry for the way she treated me and grateful I stuck around, etc. She's talking about marrying me and having kids again (which, both times, seemed like too much too soon). It seems really odd to me but I decided to trust her and for awhile things are good. She is suddenly interested in sex again, seems to have more motivation to pursue career goals/plan for the future than before, etc. We end up renewing the lease together, but shortly after she basically has a breakdown, says she's really depressed and wants to go home, but wants me to go with her. I say I don't want to, because I don't want to live where she's from. One day I remember her crying on the floor saying she's felt empty her whole adult life and doesn't know why. She soon decides she's going to move home and for about 5 months until she does it's back to the back and forth...one day she "just knows" we're not meant to be together, the next she's talking about me moving with her eventually. When she left, we were still dating and the night before she left, she said the separation was "not forever". We ended up going on a vacation together about a week after she moved, and the last night of it she sobbed about how she would miss me so much (she wasn't drunk). She ended up breaking up with me about a week later over the phone, because she said she just wanted to be single and alone, wasn't interested in dating/sex/relationships. This was also what she had said before she moved often, that she just needed to live alone to "work on her own happiness". I find out she immediately begins dating and she's now in a relationship with someone who she never in a million years would have dated before. She is physically and personality wise very different from her type and I have trouble understanding how the other person is involved in this, because she seems like an ultra-feminist and my ex hated talking about feminism/anything PC. However, she's pretty chameleon like and probably putting on a good show for this chick.

I should also mention she had a pretty messed up childhood...parents had her when they were 19, mom went through 3 marriages and left her with her grandmother a lot growing up. She would often say her parents never really wanted her, she thought one of the reasons she was gay was because she didn't get enough love from her mom growing up (really weird), I was the only person who had ever believed in her and loved her unconditionally. She also kept talking about how one of the reasons she wanted to move home was because she missed her friends, but she didn't seem to have any close friendships at all...basically just knew a lot of people she used to go out with, but nobody she'd actually talk to regularly about life.

Even writing all this it's pretty obvious I should have gotten out much sooner, but she was/is extremely charming and seemingly sincere. One of the things that makes me wonder if she actually is borderline, however, is that she never really got angry. Instead she would just completely shut down. And anytime I threatened to leave because she was treating me like crap, she acted completely indifferently. There was never any begging or anything, although ultimately she would reel me back in by being sweet again.

Thoughts? I've often thought maybe she has bipolar II, but maybe she has both bipolar II and bpd? Or maybe neither and is just super screwed up? I just want a better understanding because I still feel like maybe I'm the crazy one, which everyone in my life assures me isn't the case, but I don't understand why she had this kind of hold/effect on me.

Sorry for such a long message.