The vagina after birth

This is a question for the mommies who have had more than one child vaginally.. So this is my first child and the closer it gets my boyfriend keeps joking saying my vagina isn't going to be anymore good after birth and even though he's joking it is starting to worry me a bit lol so I'm just curious what exactly happens after birth and will my vagina return back to normal and what are some things you all did after to make sure you were good down there ????