How do you deal with betrayal?

I have just found out that my recent ex had lied,cheated and had no respect for me at all for the whole 2 years I was with him. I now know he had at least 4 other girls on the go - no doubt making all the sweet promises he was making to me. Up until a week ago I still believed he still loved me but he now has a new girlfriend and although he kept a sense of hope I now know this was just a ploy to keep me as a reserve. I feel so betrayed and I just cant deal with it. I feel like I cant trust anyone (I should add both my previous boyfriends had cheated on me - I thought it was different this last time). I feel like life is not worth living sometimes as I cant deal with lies anymore. Can anyone offer me some suggestions?