Boyfriend Left Me.

Me and my boyfriend have been living together for a while now, we’ll I found out he’d be lying to me about his ex.. turns out she’s pregnant. And he couldn’t stop talking to her because of it. I asked him to end it with her and she threatened to abort it, then she decided she was going to keep it and called his parents. They told him he was making a mistake not being with her and his parents opinion mean everything to him. I told him he had to choose.. he chose me.. well for a while. Then the DAY AFTER HE ASKED MY DAD FOR MY HAND he told me he had to take his son home to his moms because he had an appointment and he actually went to his ex’s house. Please please tell me how to get him back I can’t do this without him. I just can’t. I can’t lose him. He’s everything to me.