It's always painful

Okay so I had my son almost a year ago but after having him I didn't have any problems with getting wet. Then I got the copper IUD at 3 months pp and it went down hill from there. Well we used to kinda start without taking our time cuz with a son we kinda have to make things quick. So I thought okay foreplay will help which it did a little but still was really painful. Then we tried foreplay and lube that helped the most but it still hurt somewhat. Idk what else to do cuz I can't enjoy sex as much as before and sometimes I could be super horns but if my fiance tries to have sex I turn him down cuz I'm scared of the pain. Anyone know what I can do?