What is the main topic of this conversation?

M: We seem to be having this conversation over and over again.
W: You’re right.
M: Look, I know how you feel about my smoking. You don’t have to tell me every day.
W: I’m sorry. I worry about you.
M: I know. But work and school have me so stressed out. Maybe I’ll be able to quit after I graduate.
W: Let’s be honest. There’s always going to be a reason. After you graduate, it’s going to be hard to find a job, then there will be the stress from just starting a job, then.
M: Okay, I get your point. It’s just so hard. You don’t really understand because you have never smoked.
W: You need some help. Why don’t you go to a doctor?
M: You mean a psychiatrist?
W: No. I don’t. I mean a general practitioner. Maybe you can get a patch, or some pills, well, I don’t know, something to help you with the withdrawal.
M: Really, I believe I can quit on my own. But I’ll think about it. I will.
W: All right. I won’t mention it for a week. Then I want to know your decision. Because if you don’t get some help, I need to rethink our plans.
M: You mean you’d break our engagement over this? I can’t believe it!
W: I don’t know. I love you, but I’m not sure I could accept everything that goes along with the smoking.