It's kind of like 'that was it' when the guy cums before you do, so put your girl on the edge before you fuck her then get into a position where you can rub her clit and when you're ready to cum, rub her clit and all that fun shit so you can cum at the same time and then you don't have to worry about it.

BUT I guess a girl wouldn't mind if you came before her and did what she wanted as long as she wanted.

LUCKILY I don't have this problem either.