Quite a roller coaster ride of a relationship

So, I just ended a 1.5 year relationship after being hospitalized for suicide attempts.

I made a post here awhile back when I was deciding to try to end the relationship around December. I did, but I then made a terrible mistake. I let her get into my head and back into my life. She ended up doing stuff with a guy in a hottub during some Christmas party. This sort of ruined my naive view of the world and was the major impetus that got me back together with her. I never said anything on here because I knew I was making a mistake. After that point, the abnormal became normal and my relationship deteriorated.

I found out that she cheated on me about a week ago. I later learned that not only had she cheated on me, but it had gone on for three months and she literally was trying to keep me while hooking up with this other guy. She literally would say things to her friends about how she just couldn't decide which one of us she wanted. Clearly, I have no intention of ever speaking with her again. Her best friend of 17 years now hates her, and she has no friends at school.

I threatened to kill myself when I approached her. This was an overreaction and a mistake. I actually tried to kill myself - or I made it appear as though I wanted to kill myself becaused I tied a rope around my neck and over a pole. She tried to stop me and I kicked her to get her off of me. Eventually I stopped. The police were called and I was institutionalized. My actions were erratic and stupid. I was diagnosed a bipolar and although the Doctor blamed the entire incident on my mother's likely depression and subsequent "volcano" reactions as well as my father's affair, I believe that my actions are obviously my fault. I spent five days in the hospital - some of the worse days of my life. I'll never overreact like that again.

I'm also on medicine - 500-1000mg of depaco a day. I'm feeling a lot better and realizing that this entire process was very necessary. I got out of a terrible relationship and I actually got a lot closer to my father - he was in the same institution after he tried to kill himself.

I've learned my lesson. She certainly wasn't worth killing myself over. But learning that a large majority of my relationship was a lie - for example, she would drink and smoke pot when she explicitally told me that she didn't (it was only last night after her ex-friends and I had a long talk and heart to hear that I learned how much of my relationship was a lie that I managed to feel a lot better about it). I don't have the normal symptoms of a breakup - I don't feel as though I miss the good times or anything like that, I'm just glad to be out. But I do wonder if I'll ever be able to trust a girl again.

Also, I feel like I am already interested in another girl that I've been best friends with for some time. It feels weird, but is this symptomatic of getting out of bad relationships like mine? I'm not depressed, I'm just betrayed and still in a bit of disbelief. Her web of lies was so intricate that it was almost impressive. My mother made a comment that she thought my ex- might be a clinical narcissistic - everything she did was in her own interests. When I thought my relationship was falling apart at the end she actually made me feel like it was my fault - that I was being paranoid or nosy, even though she was the one cheating on me.