Should I keep this baby?

I have been seeing a man for 2 years, we are co-workers and have known each other for 14 years. He already has a 6 year old from a prior relationship. I recently found out I was pregnant (first time for me) I am 35 yrs old and he is 33. I am financially stable and have wanted to be a mom but this wasn't planned but I know since I am 35, I am thinking this is the right time. I shared this with him and then he said he has been holding something from me, He told me that he got his daughters mother pregnant as well. She is 11 weeks and I am 6 weeks. Clearly I am devastated. He said he slept with her once and it was a mistake and she won't get an abortion because she wants her kids to be by the same father (I get it) He seems to be more at peace with it as time goes on because his life really doesn't change as he is a PT dad already to the 6 yr old. We live in DC and she lives in Va Beach.  I am literally in a "Jerry Springer" situation. He is devastated and doesn't want me to have this baby, he likes the life we live (going out/travelling) and I don't disagree but I am older and I feel very torn on this decision. Deep down I want this and I know in doing so, he will resent me and the child. I struggle with this as he means so much to me and we work together. I don't know any women that have had abortions and personally I am pro-choice. I just feel like I will regret it forever. If I was younger I would feel more apt to consider it or at least be at peace with it. I also don't want to be selfish and have a baby that is being born into this crazy scenario with a father who resents it.

Help guide me. Give me some perspective.