Confused

I am currently pregnant and my s/o is constantly fighting with me because once the baby is here, he doesn’t want me to be around when he takes the baby to visit his family. I don’t understand why he doesn’t want me around when he goes to see his family with the baby. I have tried asking him multiple times why and all he says is “I can’t explain it”. I just find it weird and don’t understand. I need someone to talk to about this and advice so that’s why I’m posting here.

*EDIT*

Thank you guys! I also thought it was weird and concerning. I didn’t know if I was overreacting to this situation but it definitely made me feel uncomfortable as to why he wouldn’t want me around with him and the baby. I definitely won’t be letting this happen.