Help long complicated story need advice!?

am currently seeing my bf paul, for almost 2 years, he is great,loving, but i dont feel the connection like I do with billy. Me ansd billy met a 5 years ago, he was so sweeet to me, he took care of me after an accident but then he went away to school and we never hooked up.. we stayed close freidns i had feelings but started seeing my ex bf, and billy was seeing a girl from school. so billy and i got into an arguement didnt talk for months, and had a great heart to heart we really hit it off that nite, i think that he was going to kiss me but no. I told him me and bf were on break but he diddnt make move, just called the next day, wanting to hang out like friends w. when that nite we were so into each other. anyway me and ex got back together, and billy one night acted like such a jerk accusing me of using him, talking bad about my friends, being such an ***..he would apologize and do it again and again.....we didnt talk for while after that. it was so hard because he went away to school and i didnt want to get too close So I broke up with my bf, and soon he sent me flowers apologizing for everything telling me hes had feelings, I sent him a message thanking him and saying we will talk very soon and invited him to my bday party, were he pulled the same exact crap again, some my friends say he was controlling and just wanted power, others said he was sweet and protective.. I dont know he tried apologizing again, but then didnt try talking to me again until i started seeing paul...and it was too late, I thought about him a lot, i even blocked his sn on aim and still have his friend request on facebook in my inbox...he tried messaging every few months, but I dont know what to say, I really love billy more than any other guy but we have so much issues, i dont think things could work but i cant stop thinking of him, and i feel so bad because im with paul now what should I do? billy is so gorgeous and sweet, but he has such a mean side but its only wehen it comes to my friends and protecting me...me and billy havent really talked in 2 years but i still think of him and we still have weirdness between us over what happened, should we be together? me and billy have such a connection everyone in the room notices, but me and paul all have same friends, and hes not jealous and overprotective and doesnt have the temper. billy got a different sn and messaged me the other day, trying to talk and told me just tell me to screw off if you dont want to talk, but i didnt know what to say to him, i hate living like this...what should i do girls? and why would billy only try talking to me online hes seen me out since many times and just said hello and act like he doesnt know me and avoided talking to me except one time recently. I heard he was so upset about me blocking him but it was only so i didnt have to think of him...