How can i get over my ex? he even has a new girlfriend!?

okay, i dated this guy for a little over a year and towards the end of that year our relationship was VERY off and on, off and on. (to the point people would tease me about it). he talked to his ex behind my back while we were together, lied about A LOT of things, and even had his moments of treating me like complete crap. i knew the whole time i could do better but i really loved him. he was an alcoholic that had no future doing anything, i helped him to get a really good job and even got him to go back to school (he graduated from high school 4 years ago and spent those 4 years partying). i thought he had changed. well now, our relationship has ended and i thought i would be fine. i've been hanging out with friends, going to the gym, and going to church a lot. but NOW i see he has a new girlfriend and the girl is (not to be rude) a big wh**e. he likes her because he can go out and party with her all the time, and he is going back to exactly how he used to be before he met me. where alcohol plays #1 in his life. he's even moving into a house with 3 ';buddies'; who party all the time! (i guess i thought at 23 he would be a little over this stage) every time i think about him and this new girl i get the worst sinking feeling in my stomach and i feel completely sick. the worst part is i KNOW i shouldn't care and i should just move on. does anyone have any tips or ideas about how to feel better? How can i get over my ex? he even has a new girlfriend!?
once a cheater,always a cheater. (that thought within itself should help you get over him) I'm sorry you have to deal with this,i understand how you feel. :(How can i get over my ex? he even has a new girlfriend!?
the only definite answer is to meet someone much better than him for you who will treat you right