when a man is fully erect it is physically impossible for him to urinate. the tube that connects the bladder to the urethra becomes blocked so that semen can come out instead.
unless a man is fully erect, intercourse is practically impossible, his penis just will not slip into your vagina.
for this reason it is extremely unlikely and practically impossible for a man to urinate inside your vagina.
if he urinated over your vulva and some went up your vagina, i would advise washing the area thoroughly, but i doubt much damage would be done as long as he was healthy ad clean down there, after all you wee in that area all the time.