Infertility

I’ve been trying to conceive a baby with my significant other for a couple months now and have had no luck. We’ve done everything we possibly can and nothing is working. Is it possible that if I smoke nicotine that could be the cause? Would it make my sperm infertil? If not could there be any other causes of not being able to conceive, and if it is because of the nicotine what do you suggest I do?