HELP_ ME Offline

I need help! At the beging of the school year last year I ran into this guy that liked me when I was in middle school.When we saw eachother we ended up talking for hours and he gave me his phone number so we could keep in touch. So that day we ended up texting eachother and he told me he still had feeling for me but he has a girlfriend. I told him it won't be right if you do because thats not fair to her and he said what ever she dosen't know won't hurt her. I said thats not right. After school the next day we hung out before he went to football and he was asking if he could kiss me to see if there was a spark and I thought that was cheesey but i said no because you have a girlfriend and he tryed to lean in on me and I pushed him away. I told him to leave and go to football. So mouths passed by and I started falling for him but I tryed to stop myself because it wouldn't be right for me to do something like that. He asked if we could hang out before winter brake becuase he was going to go out of town so I said yes. So we went for a walk and we ended up in the libaray by the school to pick up his brother. We where alone in this hallway in the libaray and he asked again if he could kiss me just once and I said NO! and he said Please. He leaned in on me and like the DUMB ASS I am I let him kiss me but I felt something go off inside of me and it felt weird. So after we walked back in front of the libaray and he said WOW! and I said I feel soooooo bad about this. He said don't worry and I was like what if she finds out and he said she won't. He told me he was going to brake up with his girlfriend for me and I said thats not right you should just stay with her. So after winter brake some how she found out and he put all the blame on me and he was telling her that I was the one who kissed him and that I made the first move but it takes two people to kiss. I just started to ignore him and mouths passed by. He started talking to one of my bestfriends and he was asking questions about me and he also said I wan't my girlfriend to brake-up with me do you think she will kiss me again. They ended up staying together but his girlfriend dosen't want him to be talking to me anymore. Now he is really fucked up to me now and we are not so close as we used to be and I miss that. I wish that day had never happend but it did and now people are telling me when he brakes up with his girlfriend hes going to come to me and that not hleping me get over him.