Marijuana

My boyfriend and I have unprotected sex and he doesn't pull out... We've been together for four months and half been doing it this way since we started being active with each other. And each month nothing has ever happened. So I did some research and found out marijuana can Significantly effect sperm count. We both want a child, and I brought up to him he has to stop smoking but he just hasn't yet. This month I haven't gotten my period and have taken two test and they both say negative. Am I stressing out? Eatting wrong? Could I be and because of the marijuana it's not picking up on a at home test?