Newly pregnant by cheater, what should I do?

My boyfriend and I have been together for a little over 8 months now, and I knew he had some baggage when I got together with him in the beginning. He had 3 children already by 2 different women and he had recently parted ways with his ex when we met. I myself have 2 children from a previous relationship so I did not see that as a huge hurdle to jump, although I was wary about his involvement with his ex, since she was not the mother of any of his children and she would text him every now and then. I had suspicions before and questioned him about it maybe 2 months prior. So, yesterday he tells me he had been cheating on me for the past 3 months with her. He gave me the clic sob story of how he has fallen in love with me and he, being confused with his feelings for her and his new feelings for me made bad choices *Crap*. He said he didn't mean for it to happen, he wants to be with me, and he was sorry (you know the crap men dribble out of their mouths when they know they have stepped in it). Now, he told me this because (and only because) his ex is 8 weeks pregnant. We live in the same area and have acquaintances in common, so I would've eventually found out even if he didn't tell me. I pretty much refuse to continue a romantic relationship with him at this time because, although I do care about him, I can't see myself even trying to take him back after he has betrayed my trust like that(even this early in the relationship). Friday, I took a HPT and I happen to be pregnant too (about 4 weeks based on my LMP). I have not informed him of my condition yet, as I was so irate with him yesterday that I pretty much told him to kick rocks. But I am internally torn on whether or not I should terminate this pregnancy or if I should even tell him that I am pregnant if I decided to keep the child. I don't particularly want to become entangled in his mess for the rest of my life, but I am a bit ambivalent when it comes to the subject of abortion especially when it comes to a situation like this, after all it's not the child's fault. Where practically I can see an overwhelming benefit of cutting all ties I morally have an issue because I was raised Catholic and believe abortion is wrong. Honestly I see a whole lot of drama coming into my life no matter what I do. What would you do if you were going through this, and how would you handle it?