how can I convince my husband to quit smoking and lose weight to increase his fertility?

please no rude comments I'm really looking for support/advice and anyone who may have personal experience with this. my husband has been a smoker for almost 10 years and he's tried quitting about 4 times but it's been so hard for him because hes surrounded by other smokers at work and his personal life. hes been slowly gaining weight over the last few years and its getting to the point where if he doesn't do something now he'll end up having a really really hard time losing it later. i love him no matter what of course but i can't help but wonder if the reason we aren't pregnant yet is because of his smoking and weight. i tried hinting at it a few times but he just stays quiet. hes pretty sensitive about his weight i just don't know how to help him and motivate him. again please no rude comments keep those to yourself. thanks in advance ladies