The only way to marry my girl is to quit smoking, but I can't do that!

My girlfriend says she will only marry me on the condition that I quit smoking. The problem is, I've been smoking for 19 years and I don't know how to quit. But I love her so much and I don't want to loose her, so what do I do? Should I pretend to quit? But for how long can I carry on with the charade, because sincerely, quitting is not an option for now.
Help.
Sincerely, Mike.

I think with men, it's either you take them the way they are or you leave them. It's difficult to change a man. Not impossible, just difficult. Over to you guys, Mike needs your advice.