Running out...

Okay so for some people this may be TMI, but here goes...

My husband and I have been trying to get pregnant for about four months now, so we've only just began the journey to parenthood together. I obviously haven't became pregnant yet, and I know it's still way too early for concern, but I have a question... Do any of you other girls have trouble with your husband's cum running out of you after sex? I've done some research and apparently this is relatively normal, but I can't help but think that this could be playing a role in us not being pregnant yet.