Recovering addict & TTC

So I've never used drugs but my boyfriend has. He had a meth addiction for 3 years but has been clean for over 5 years. He has two children from before his addiction who he is a great father to. We have been ttc for several months and nothing. I am healthy, and so is he now. He smokes weed occasionally but I don't. Just wondering if those years of meth use could have totally killed his sperm?