Bf thinks he’s infertile

So, my boyfriend is a recovering drug addict, but still occasionally drinks because alcohol is genuinely not a problem for him, which sounds contradictory, but it’s true. I’ve known him for a couple years and know everything of his past, but I’m worried that due to his long term addiction (almost 1 year off drugs), and still occasionally drinking, that it’s going to be hard to conceive. He was with the same woman for years (but always forgets that she was on birth control) and never had pregnancy scares. My cycle has almost always been exactly every 28 days since I was like 12, but I’m just worried our chances are slim. Has anyone had any similar experiences or advice? Please do not judge him. He’s had a hard life and wanting to be better and start a family with me.