I will try to make the long story short.
I have been with this guy for 2 years and a half now, at the beginning we were just friends with benefits, he said he was OK with it but one day when he asked what had I done for the weekend I said I went out with other guys and he went nuts, he asked me to step out of the room cause " he didnt wanna hurt me", I felt bad so I walked towards him and I said sorry but he pulled me out of the house and he hurt my finger, he apoligized and gave me a pair of erings.
I htought that if I was his girlfriend then he would feel better but he was extremely selfish for example he knows I hate giving him oral but he will really push me into doing it so one day after I gave him oral I asked if he had ever try the taste of his ***, he said NO that's disgusting, so I asked why does he want me to give him oral if he thinks is disgusting so I took a bit a *** and put it in his mouth, he spited in my face, so I broke up with him. After few days he called apologized and I was like OK.
After that I started realising he was kind of using me sexually but every time I tried to leave I will come back to him. I try dating other guys to see if that will help me realice there are better guys, but it didn't actually one time he found out so now he uses that saying I am such a cheater that's why he cannot treat me nicely.
Last month I went to montreal to study for a month and I thought I could forget about him, but when I am away I feel the need of talking to him and give him explenations about what I do. Then I realice my behaviour is not normal and I try to leave go out with other guy and it doesn't work it just helps my boyfriend to cal lme slut and make me feel quilty, when I got back from montreal he found out that I went out with other guys since he has all my password for all my emails and even Facebook, so I told him the reason I go out with other guys is because I am not happy with him and I don't know what to do, he went nuuts he try to intimidate me by twisting my arms and stuff but I took apair of scisors then he chucked me, he asked why I don't love him, why do I hurt him he said he wanted me to feel his pain, at the end I was so tired that I just went along with him and had sex.
I just feel stupid I know wats going on but I don't know how to stop it.

Somewhere in your life you lost a sense of self worth.
When you get that back, you won't put up with this for an instant.
No, you don't tell someone he is abusive, you LEAVE. You change your passwords (which not even spouses share usually). You don't walk towards him when he warns you to walk away. You don't be friends with benefits, which is 99% of the time a one-sided arrangement. You don't explain to him, because it's pretty clear that you aren't able to. Break up from far away, make it clear and simple and SHORT. Use friends to gather round you. Find other things to do. Good luck. Report back if you can.

You should get a lot of input here, some you may agree with, some, not so much. But having been in a couple of abusive relationships, let me start the ball rolling here.
First and foremost, violence in these situations tends to escalate.
Secondly, actually "wanting someone else to feel pain" is vengeful and not a very desirable personality trait.
Third, (at least in my case) going back for more was a simple case of familiarity, and fear of the prospect of having to start over.
And last but not least, self-presevation must come into play at some point.
It seems that you have tried to put it to rest and be done with him, so I think the self-preservation may not be a big issue for you.
It also sounds that there may be some emotional abuse involved, that can be very damaging to the psyche.
Even if you are a strong person.
Step back and analize your feelings and decide for yourself what is best for you.
If you are unhappy, then it seems your best choice may be to cut all ties, suck up the loneliness that may ensue and rely on self, spend free time with family and friends to curb the desire to return.
There are kind and gentle men out there, there are also some real jerks.
Good Luck and I hope some of this helps
Sam
Sorry, just a quick addendum:
Why does he have access to your personal info, are you allowed to have access to his?
If not why? And does he have it because you offered it up or did he insist? If so, this may imply a certain amount of insecurity on his part.

Thank you this is actually helping a lot, it is actually painful to realize I am refusing to move on to better things just like joypulv said somewhere I lost myself respect, and I need to start working on getting it back to have the streng to suck up the loneliness.

That's the spirit, work on that self-worth. Surround yourself with positive people and remind yourself of the things you like about YOU. Keep us posted, sounds like your off to a good start. You may even surprise yourself.

You never need to "feel quilty [guilty]" (8
Why not change all your passwords?
You are free.
You don't need to keep going back to a manipulator - he is no man.
In life, there are so many people. Everyday you can meet new good people.
The world is so big - you can move, change what you do, where you live.
Be strong - you are.

You don't need to listen to him, or me or anyone, ever.
The answers to all you can ever need to know are inside you already.
You can go with your heart.
8)