What to do with my Dad? Please I really need some advice :(?

Cut off contact with him, you would be a lot better off. Sounds like was just calling you out of guilt and he sounds like an asshole for choosing his girlfriend over his child, which is exactly what he did. You've made it 18 years without him, you can make it now. No need to even contact him to tell you this. He never bothered to be a father when it was really important, why would you owe him an explaination? Leave him and maybe he'll know how it feels.