Is it sanitary to have sex with dirty nails?

basically, my boyfriend is a construction worker so he gets pretty dirty throughout the day which I don't mind, it's sexy! but he's very like germaphobic or whatever like he will touch gas station door and refuse to touch my face his face.. me on the other hand I don't have that problem.. anyways his finger nails sometimes have dirt under them and he cleans his hands well it just sticks.. he doesn't like to touch my vagina or finger me or play with me too good because he says his nails are still dirty which I understand but a lil dirt don't hurt right? I'm okay with it! it's not that dang bad. but is it unsanitary or no because I know if he scratched me it could be a problem but I just wanted him to rub the outside a little lol!!??