Husband won’t stop smoking

So we have been having trouble conceiving and my husband has had many health scares in the past. We went to a fertility information session last night and they said that a man smoking not only does it reduce he chance of getting pregnant but also increases the risk of childhood cancers for the baby (4x). He said straight afterward that he could stop anytime as he only smokes occasionally but has continued to smoke. I’ve tried many things and I’m not sure what to do now.