20 years his senior... Please help.

please no judging me. I already feel bad and stupid... My boyfriend cheated on me with a woman 20 years his senior (he’s 33, she’s 53) my whole pregnancy. Even after I found out when I was 4 months pregnant, I kicked him out but then took him back 3 months later and then I found out on the day I went into labor that they were still sleeping with each other. Our baby is a week old and I find myself torn about leaving him. Up until I found out about the cheating, you couldn’t have told me that he wasn’t the perfect guy. He accepted my other 2 kids and treats them like they’re his own, pays the bills, takes me out to lunch weekly, helps take care of my grandmother and really treated me like a queen. I was shocked when I found out about the cheating and even more shocked to find out that he was still doing it. I want to kick him out and move on but I feel like I need him financially and physically (he takes and picks up my kids from school everyday and helps me with everything in the house and takes good care of the baby as I’m still healing from my c section). I also feel like my kids would really miss him as they kept asking me where he was and when he was coming back the last time I kicked him out. The old me would have been moved on without even a thought, but I feel like I can’t do any better and that I’d be sacrificing a lot if I let him go. As for now we have just been going on about our day like nothing ever happened but I’m extremely depressed and I just need some good advice please. The woman he’s been sleeping with knows all about me and that we were expecting a baby and she didn’t care in the least bit. They work together and even tho he’s texted her and told her that he doesn’t want anything to do with her anymore, he did that the last time and they still ended up back together. I feel like such a fool.