Boyfriend dilemma

I'd been dating this guy for a few months and things were really wonderful. Every morning when I got up he would send me a text message saying, "good morning beautiful have a good day'". And every night before bed he would send me a text saying, "goodnight beautiful, hope you sleep good." He always texted me during the day to see how my day was, we spent nearly every day together for 3 months. We got along perfectly, we laughed, would hold hands while sitting watching tv. Great sex, everything was perfect. He told me that I made him happier than he's ever been, and he didn't think he could ever feel this way about somebody. He finally introduced me to his kids and their mother, she took one look at me and turned around and walked out of the house. The next day she started texting my boyfriend telling him that she still loved him and wanted to be a family (she's married by the way). Right before this happened he asked me to move in... And 2 days later he's telling me that he still had feelings for his ex. I tried to break up with him but he didn't want to, he said he was just confused and wanted to be with me. So I let it go, because I knew how much family means to him, as his mother left him when he was a baby. So I was trying to be understanding. Things were fine again finally when this girl he used to sleep with heard that he was in a relationship and was happy. She contacted him and said she just had a baby and it was his, even though it's named after the guy she's been living with for the past 7 yrs. She also starts telling him that she loves him and wants to be a family, so I once again am out. As he tells me he still had feelings for this whore. (She has 3 kids by 3 different people and she's only 25, is a junkie, and has no teeth). A DNA test hasn't been done and she's stalling doing it. I feel like this whole thing came about because she found out about our relationship. I feel like he is afraid to be happy because of mistakes he's made in the past, so he pushes people away before they can leave.i'm sure he cares about me but these tramps are just messing with his head because they can. Or maybe I'm wrong and he is just a douche bag that used me and screwed with my heart because he could. I just found out that I am pregnant with his child. I don't know what I should do. Do I try and wake him up and make him see what's right in front of him or is he not worth the fight. Any insight on this situation would be greatly appreciated.