Ok here's the story, was with this girl on and off for close to 2 years. It was up and down the whole time, most of the time I felt unshure around her and later she expressed the same. To me she was always talking about her ex's and how bad they treated her, and this may not of been everyday but seemed pretty close. She even seemed to compare me to them, if I did anything they did, she would always tell me so. I don't have a lot of self-esteem to begin with, but while I was with her I lost all that I had, and I could only take so much of her and I would break up with her. A few days or weeks would go by then we would agree to get back together. After awhile I figured out one problem I had, and it was she reminded me of the way my mother treated me growing up. Always critical of the things I did, seemed like I wasn't aloud to be happy or have my ownthings that I liked. After this final break up, which is now a month and a half past, we've talked at different times and I've come to the conclusion that she pretty much blames me for most of the problems in the relationship. Still waiting for her to take some blame for it. The thing that is bugging me the most is that literally the next night after we broke up she started seeing this guy from one of the bars she hung out at. She always liked going there cause of the attention she got from the people there (red flag there). Now she's been with him since we broke up and is allowing him to stay over and I can only imagine having sex when her daughter is home. This was a huge no-no when I was with her. Oh forgot to mention I live around the corner from her house, and can see her front door from my building. I really need to move on, but I am having probably the hardest time right now. I feel like a friggin stalker cause for some sick reason I have this desire to know what she's doing. Tonight we talked things seemed better, but when I called her later to see if we could meet again to get some more issues taken care of, the first time she didn't answer, but the second her daughter did and said she was busy... that hurt... I know a lot of this is my own doing, but need some advise please. Thank you in advance...

NC is the solution even though your situation is hard as you live so close to her. Keep yourself busy at home so you don't have time to "stalk" her (because it's what you're doing, you are stalking her) or take a vacation and go somewhere, invite your friends over if you want to stay home, you can be anywhere but near that window. Do you have any way to move somewhere else or stay with friends/family for a while?

Trust your insticts, you wanted out for a reason, there are just too many red flags there to make anything work. You think she moved on too fast and this is probably why it's hurting so much. NC will help you heal and actually move on. You have a lot of work to do on your self-esteem issues, you may want to seek counseling.
I know it hurts but you have to realize that she just replaced you with another guy she will probably treat like she treated you... and make him unhappy like you are now. Why would you want that back?

^ This is the perfect response, wow... pretty much literally nothing else can be said. I came out of a situation like you, almost EXACTLY like you, its creepy in a way... I know precisely how you feel and yes you'll start to realize your much better off without her

Take the rather subtle hints that she isn't feeling the same as you are, and save all that effort for someone who is.

She isn't worth the efforts your doing.