Please answer i dont know how to handle this myself....?

im not the one to easily trust someone.but with "him" i trusted him from the moment i spoke to him.i fell for him hard but he had a girlfriend at the time.he promised me that i was all his. of course i trusted him.he one day slept with me and then maybe a couple weeks later never called me back.then 8 months later i spoke to him again and he told me how much he thinks about me and how he always checks my myspace bulleteins..he tried speaking to me a couple times through the 8 month period.but i wouldnt let him.now we've been together for 9 months..we used to spend everyday together until things started to get bad between us.he tells me how much of a mistake it was to of stayed with his girlfriend.she cried to him so he suckered in and stayed with her.he tells me this was a mistake and how much he loves me now...and he truely wants to get married with me.i can't seem to trust him with girls or anything..at all.i need an answer that someone can put themselves in my shoes.

i know i asked this before but only one person answered and it wasnt the answer i was looking for. im not trying to marry him RIGHT now. im kinda too young to decide that yet. and i just want things to get better between us because honestly it has gotten worst. and i mean horrible. and its all because of the stupid past. i repressed all my feelings after he did this to me.. but i was in the worst state emotionally, the worst ive ever been in when this happened. and now i kinda hate him but i do love him. i hate him for putting me through the toughest time emotionally but i do love him for everything we have been through anad everything he has done for me.

If I had to describe this with a metaphor, your situation is comparable to someone periodically picking at a sore that's not healing. Give yourself some time away from him completely, and let time bring things to a clearer light.