Marijuana and TTC

Hey everyone! Not TTC just yet, but I was wondering if anyone had any experience with this. I do not smoke marijuana or cigarettes, but my fiancé smokes marijuana and cigarettes every day after work. He’s 35 and I’m 28. Both of us are in pretty good health. We both have full times jobs and pay our bills on time or early so his usage does not affect his responsibility. I’m just wondering if his usage could possible affect our ability to conceive a healthy child. No family history of any fertility or developmental concerns on either side. We’ve talked about when we are trying to conceive my fiancé would decrease or stop smoking until I become pregnant. I’ve read different things online so I’m just wanting to know different experiences. Thanks!