Need advice

I have a fiance that loves me beyond words can describe. I love this man truly. We want to have a baby we try off and on you know it can be exhausting at times with work and our everyday life. Here's what I just dont know what to do first off sex is ok it goes by fast really fast like no more than a minute so that gets to me cause I can't orgasm second he smokes a lot and that can affect his sperm. he don't want to stop though. do you think I should just hold off on marriage sex n baby. it's breaking me and I need advice HELP!!!!