He cheated.......(this is a true story) need advice asap!!?

My fiance cheated on me with my cousin, she ended up having a baby by him...he's very apologetic and keeps apologizing...she said she doesn't care oh well..she doesn't think shes done anything wrong. I broke up with him, even though I'm still completely in love with him and started dating someone new...but i don't like him like that. I like him as a person but not relationship and i find myself thinking about my fiance. I blame myself for everything and i cry all the time...its been months and i still cry. He wants to work things out but I can't do it...that makes me cry even more. I'm miserable because he was my first love and i've been with him for years. She was my cousin and she doesn't care that she hurt me like that. I'm tired of crying all the time, but i dont know what to do??