I don't think my boyfriend has healthy sperm

I've gone to the doctor and they've checked my ovaries and cervix and everything is great. They say I'm healthy and when I'm ready to have children I'm good to go 💕 but I've been thinking lately, boyfriend and I have sex like almost every other day or every two days and he never pulls out. We're planning to marry this year. He has a beautiful little girl from his previous relationship. However we've been having intercourse with no protection because he's my life partner. But it keeps crossing my mind that I haven't become pregnant. I initially thought it was me and went to take tests and everything. They said I'm perfectly healthy. I mean I'm not desperate to have a baby right now but I mean law of averages it would only make sense that I would/could have become pregnant at least once with the amount of sex we have and completely no protection. Should I ask him to check once we get married or is it wrong if I asked before. It wouldn't change the fact that we're marrying whatso ever. I just would like to have children and this has been on my mind for a few months now.... 
 
Any feedback would really help 
Thanks 💕😊