Oh boy

Okay ladies I think I may have gotten myself into a bind, please refrain from judgement until you hear the whole story.  My SO and I ended up having an unplanned pregnancy but decided to have an abortion because we were not ready to be parents. I recently got back from vacation during which time I went to visit my ex boyfriend in order to end the romantic relationship that still lingered between us (primary reason my SO and I parted ways but trying to work things out). While visiting my ex boyfriend, one thing led to another and we ended up having unprotected sex twice with him cumming inside me.  
I got back from vacation Sunday and my SO who I'm trying to work things out with picked me up from the airport. We got back to his place and due to our intense feelings ended up having unprotected sex, but he didn't cum inside me.
I am very aware that there's a possibly that I am pregnant. But the question is if I am, who would be the father? I know it was dumb to do after an abortion but could really use the advice.