Single and pregnant...

I'm 16wks pregnant and am single. My LO's father left about a month after finding out we were pregnant. He decided that he wanted to go back to his ex. He felt that he wasn't over her yet. He even gave me money for an abortion. We had been seeing each other for 4 years and the whole time he and I were seeing each other he would fill my head up with how he was not happy and leaving her. 3 months after leaving her and we decided to officially be together I got pregnant...now he's gone. It's been a struggle. He even has told her that, "Nothing will stop us from having our first baby together" because it's what they both want I guess. I'm devastated, but I guess it's what I get. Not trying to feel sorry for myself or want anyone else to, just wish I knew what I know now and that is to leave knowing he wasn't done with his girlfriend.