Need some type of closure: Heartbroken by a bipolar ex.

HELLO! I would like to start off by saying I do not bipolar disorder, my ex fiance does!

I will try to get as much detail as possible to this story for I am heartbroken and very confused. I understand not everbody with bipolar has the same personality, but I need help because it's been 6 months since we broke up. I don't really understand bipolar disorder and I will admit I should of research while we were dating. It would of probably helped a lot!!! I still have not got over him because there was no closure on his part. Please help me as much as you can Everything is appreciated.

My ex and I were high school sweethearts. We dated for two years and we were engaged/ planning to move in with each other. At the beginning of our relationship I emotionally cheated on him with two different guys because at first I wasn't sure if I wanted to be with him. After putting him through that I looked in his eyes and could see the pain he was going through. You see, he was use to his girlfriends picking another guy over him. No one ever really gave him a chance. He also was in a foster home for almost all his life. He never lived with his mom because she was bipolar too and very controlling. I think it was much to that story then what he was telling me. His dad is bipolar too btw! Anyway I fell in love with him, that's why I stayed with him. All those other guys just were crushes and nothing more. I knew I wanted to be with my ex!
About 3 months after our one year anniversary, he admitted he "tried" to cheat on me because of what I did in the beginning of our relationship. I was very upset because I was nothing but completely honest to him during that time and he hide that from me. I mean I know what I did was messed up, but you are suppose to forgive people when they mess up not hurt them back. Pretty much that's when our relationship started going down hill. We argued because I caught him texting other girls and basically flirting with them. He would call them sexy and stuff like that. Which I think is inappropriate for someone that was so hurt about me hurting him. His mom was coming back into his life and she would control him and threaten to kill him if he didn't come see her. I got pregnant by him but aborted the baby because I didn't want him to be tied down to me forever. Almost our second year of dating I caught him texting another girl and he was really talking dirty to her. Like he was saying he would ###$ her and $#%^ like that.
I freaked out and tried to kill myself because I was so hurt that he was doing this to me. Within that month he dumped me and lied to me about why he was dumping me. He said that school and work was getting in the way. After that I gave him space and we had sex twice after that. Then a month pass by and he hasn't called me, so I called him and found out he is was dating that girl he was texting sexual things to. I was so hurt and heartbroken. I don't understand why he did this to me. Almost all the stuff in his apartment my parents bought him. I would always cook and clean for him. I would plan fun dates for us to have and even invited him to my family functions. My family loved him and were so happy that he wanted to marry me. For our two year anniversary I saved up 300 hundred dollars, so we could have a yacht cruise and a private dinner. <<<<I also didn't have a job at the time so that was a lot of saving for me. This girl he is dating has like three children that I am guessing is not his. I am just so confused and hurt.What sucks the most is that when I was going through my cheating, I told him everything and kept him update because I had respect for him. He didn't do the same in return,so he just hide everything! He even made a new facebook behind my back and so he can show her that they were in a relationship. Please help me figure him out so I can have some closure If you need more details just ask and I will provide it.

Also I can't ask him for closure, he will not tell me anything...When we broke up and I found his true plan, I would ask why but he said I don't know. Btw that was his answer to everything, "I don't know"! I am the type of person that tells me significant other everything my answer is never I don't know. I just don't understand please help

Also sorry for my bad grammar! English is my second language