Sex and cumming while pregnant

Ever since I got pregnant its like my man's natural instincts are kicking in, he wants me all the time haha which is really nice! I understand that sex is okay but he thinks now that I'm pregnant he can cum in me. I'm a little hesitant to it because I'm not sure If it'll hurt our baby or thin my cervix somehow.

Anyone got any good advice or are in the same situation?

UPDATE: thanks ladies. I know it was a ridiculous question haha I grew up with religious parents and I was never allowed in sex Ed class or learn about that kind of stuff. So I wasn't sure