Always Answer, but never ask....here it goes. (9 year, 2 kids- relationship)?

So, the past 9 years has been very up and down to say the least. First started off very innocent...i was 17 and so was he. I wasnt allowed to start dating till i was 16, and didnt...wouldn't even talk to a guy because i knew it would led me to want to date. But, after turning 16 and starting to go out and meet people, i met my boyfriend Bryan. He was working at a bowling alley and i was going there with my mom. He had a gf, so i didnt say anything...expect to a couple of my friends. Well after he broke up with her...word got around..and we started dating. He was friends with a group of guys that werent all that great. Drugs, Partys...and just teenage troublemakers. Things went good for a while. I would go places with him...even though i mostly just sat there with his friends a hung out. After a while...he would invite me less...and i started to sell my friends out more and more. I wouldnt want to leave my house...thinking he would come by (he would call sometimes and ask if he could come by) and i would never want to leave because i didnt want to miss that chance. You have to understand, i come from a very loving family...they raised me well, was never a trouble maker ever. I was ALWAYS taught and believed...you treat a person the way you would want to be treated. I seriously live by that...even today. Well, after weekends at home and never really going out with him too much...i started to check his phone (bad i know..) but i started to see texts from girls...and started to be my own Private Investigator. I was good, lol. I found out he would lie to me all the time. (side note...we were each others first...about 7 months into the relationship) I would see his car parked infront of girls houses...everything. I confronted him when i would have proof he did something. Then, he said we need a "break" one day...no reasoning was givin to me. Then...about a week later he comes over, says he needs to tell me something..he cheated, he had SEX with another girl. But he knows it was a mistake and wanted to work things out. I FORGAVE him (??? i know!!!!!) Well, he would still talk to other girls..flirt through text...and there were always girls around his hoe of friends (The guys) and i knew he had easy access to girls at any time. I feel thats why i was never invited. Fast forward...we finally reached a point in our realtionship one night..he came to my house (he would sleep there most of the time...but come in at 4am or some crazy hour)..he was on some kind of pills and says to me that he has done something that i would not forgive him for and that he should just move to his moms...but he was soo ****** up i couldnt get him to finish. He passed out and i was left sitting there thinking of this **** all night. So in the morning i woke him up and he couldnt believe he said that to me and said again that he was just going to move to his moms...and that we should just stop the relationship. He was crying and so was i...it was so crazy. We worked it out..and stayed together...that day he confessed to everything bad he had did in our relationship and we started over. Years went by and i got pregnant. We moved out of my moms and in with his sister and her fiance and child. Bad idea, but on with the story. We had our son in Oct 05'. The day he was born he was brough to the NICU because he stopped breathing. 3 days later we found out that he had Down Syndrome and his heart needed reconstructing. In Nov 05 he had open heart surgery. This was so hard for me...im crying thinking about it..but he was my rock. I couldnt imagine going through that with someone else. We still had problem, kids bring stress and we were never really great anyways. He was my first and only love. Then in November 2007 we had our baby girl. This pregnancy was difficult for me, i had to go to alot more dr appts for testing to make sure i dont have another child with downs. She is thankfully a healthy baby girl and learning so fast. But, we are just always back and forth. We have seemed to just lose all respect for one another. We fight, he says mean, mean things to me..and its just hard. We are two different people...raised two different ways. His interests are WAY different then mine. We dont like the same things..mostly. I decided in November of 2008 that i was going to go to my moms and we were going to see what happens...well by Decemebr 31s i was back living in the house. It was hard living with my mom again. And i wanted us to work...things were going ok. Now here we are September 09 and i have lived in my own place for 2 months. I moved out of the house and am renting a 2 bedroom place for me and the kids (i have them one week and then he has them one week...back and forth they go.) Its hard, i never wanted to see this for us or our kids. I love him, im so comfortable with him, but i dont know what to do anymore. I dont blame him for all the things in the past...i forgave him and we dont really bring it up. I moved out because we cant keep going