Is she even into me anymore? / What do I do?

[biger_beter]

So I was going out with this girl for 3 years, ever since I was 16, and she was 15. Things were amazing, we experienced everything together, and were just extremely happy for those 3 years.
Then came senior year of highschool, and we both went to different universities very far from each other. We handled long distance VERY well for the first year, and slowly we started getting insecure, she started controlling me, and things just kept going downhill. We've broken up for about 8 months now, but still talk.
Initially things went really bad, we went on a break, and she dirty danced with another guy. She told me about it the next day, gave me her password, and I saw all the pictures. I was devistated for the longest time, she tried to contact me, but I wouldnt give in. A while after that we started talking again. With her being so far away, and me having trust issues with her, and her being such a social person, it just left me very insecure all the time. Everytime we fight and stop talking for a few days, we just end up talking again, she starts crying, and I just melt. She keeps telling me that she wants to make it work, but then one way or another she messes up. She'd do things that a girl in a commited relationship shouldnt do, and it just hurts me. (its nothing sexual btw). We talked yesterday, she wants us to work on getting the trust back, she swears she wants to marry me someday, and she promises she'l work on gaining my trust back.
She even asked me to talk to her father once im done and get us engaged.
She's lied to me alot before, and I just dont know if I can trust her again. I'll admit to being somewhat psycho and unreasonable sometimes, and according to her, that's why she wasnt always straight forward.
I'm very scared i'll end up hurt again, I just dont know what to do..
All I know is that i'm crazy in love with her, and im scared shitless she doesnt love me half as much.
Sorry if the english isnt perfect (not my first language )
Thank you all in adv

[vashti]

Going to university is all about having the kind of experiences she is having... dancing, flirting, parties, etc. YOU should be experiencing this, too. This is why (IMO) it is best to be unattached when going off to university. Why don't you consider NOT being exclusive, but having dates together whenever possible? That way, you could both be doing what you are supposed to be doing, and maintaining a connection for later on.