Am I wrong here?

My bd and I have been together on and off for 5 years we have a beautiful daughter and I’m pregnant (38 weeks). Last year he got physical (Nov 2020) and I told him to stay w his mom and we can figure it out just needed the space the regroup (first mistake). We’ll fast forward we’re ok we fix things and then in April his mother decided to tell me about him cheating on me while he was staying w her and how she was hoping he’d be the other girl and leave me. A month later I found out he cheated on me with ANOTHWR girl and potentially had a baby on the way. Well I was already pregnant I broke up w him and he’s been very active in the pregnancy and w our daughter. Christmas they want all of us to go over (including me) so they can open the presents we got them. I don’t want to. I feel like there’s no need for me to be there especially after her little confession of how she’d hoped he’d leave me. And I also am the reason his family ever got gifts for birthdays and holidays and I didn’t get them a thing as that’s not my obligation and he didn’t because he never does.