Just had a baby, cheating boyfriend

I just had a baby two months ago with my boyfriend of almost seven years and the past week I’ve noticed him texting someone named “As” in his phone knowing that’s not a real name so I got curious but just tried to tell myself that it’s a friend or something but tonight he left his phone on the bed and fell asleep on the couch and I was in bed feeding our son and decided I needed to look... he’s fucking talking to some girl I seen a picture of her they’ve talked about meeting up or hanging out after he gets off work (he works crazy night shift to where he can get off at anytime) but nothing sexual that I seen, I had to stop looking. I literally don’t know what to do and this isn’t the first time either. I just had his baby were supposed so be happy, I thought we were. I just don’t get it I feel so fucking stupid and worthless, I just don’t get why I can’t be good enough for him but he still keeps me around like if you wanna go talk to other people tell me so I can pack my shit and leave. What does he keep me around for his house bitch or what?? And I know I’m not an ugly girl I’m not the best by far but not ugly I might have some stretch marks here and there and have a few extra pounds mainly in my ass though my fuck I JUST HAD OUR BABY!! And it doesn’t have to do with sex either I know for a fact because I have a higher sex drive than him at the moment and we’re freaky together lol. I’m laying in bed searching for an answer, slowing falling apart... why can I never be enough??