<human>: My boyfriend and I have been together for a year and some change now. In the beginning he didn't care if I smoked or not. I have been smoking since I was about 13. My worst was about a pack or two a day but I've come down since then.

All of a sudden he's saying he wants me to quit now. He reasoning is because my dad was diagnosed with cancer, and my father has been smoking since he was 16. He's in his 50's now. My boyfriend's dad also had a heart attack from smoking. He's now worried that I'm more in danger of dying at a younger age and he says he "wants to spend the rest of our lives long and healthy, not short with pain and suffering"

I understand his concerns but does it make sense that it's a deal breaker? He doesn't understand how hard it is to quit because he was never a smoker. Ever since my dad was diagnosed and his dad had a heart attack (two months apart from each other) they've both quit smoking. I understand he wants what's best for my health and he's seen two people close to use get really hurt from the habit, but is he out of place in demanding I stop smoking or he's leaving?

Can you succinctly summarize the text in 1-3 sentences?
<bot>: My boyfriend wants me to quit smoking even though I really don't want to. Says he can't stay with someone that will choose to kill themselves slowly.