When we smoke (pack a day or more for 20 yrs), we are addicted to a myriad of things. It took me 3 times - 3 real attempts lasting a year or more - before I broke free.
I didn't drink for 10 years after I quit because drinking is linked with smoking.
I used the gum because I was addicted to the nicotine which you only realize after a week without a smoke.
I was addicted to having something to do with my hands and started playing spoons and forks and pens.
I put on 15lb because once you eat a thing you keep on going having no way to know you have eaten too much.
I had to stay away from smokers and smoke.
You cough up gunk for a year or more - I did because I smoked so long.
To this day, when I smell smoke outside a building I track down who is smoking and not considering their health (and I get a secret joy smelling tobacco smoke).
I quit in 1992.
ETA: I forgot to mention that the walls and everything in your house smells and turn yellow, and your dog can get real sick from 2nd hand smoke. Do it for your dog, if not for you.
LOL! Me too--quit in 1992 that is. I actually used to quit periodically if I was dating someone who didn't smoke but cigarettes in California were about to go over $2 a pack and my Scots ancestors were turning over in their graves at the thought of tossing $400 a year down the drain.
AND luckily, I spent Christmas with friends who had a 4 year old with a full blown green snot cold--she gave it to me. Must have been a new and particularly virulent cold because I was so sick with it for nearly six weeks that I didn't even want to smoke. And I've always ended up with bronchitis after any cold and with the bronchitis after this one I was still hacking my lungs up months after the actual cold. By the time I'd stopped coughing, gotten rid of the bronchitis it occurred to me that since I'd gone over four months without smoking that it was a perfect time to actually quit permanently.
I didn't go into a bar or restaurant that served liquor for nearly three years--the association was too strong--booze--YEAH! grab a cigarette. (Wasn't quite as bad as a friend who quite smoking after he retired from the military after 20 years and a three pack a day habit--he'd been out and a non-smoker for 10 years when we worked together and told me the first thing he STILL did in the morning when he woke up was reach for a cigaretter. Even though there hadn't been one on his night stand in over 10 years.)
I also quit hanging out around people who smoked.
I took up doodling on scratch paper, napkins etc to have something to do with my hands.
I gained weight and still fight that.
But I mostly quit coughing. I don't get as many colds. My clothes don't stink like smoke. And I see from the signs around here that cigarettes are now, on sale, at around $5 a package for my chosen brand. My Scots forebearers are now quiet in their graves since I'm not blowing (umm how much would it be?) around $1,700 a year in smoke.
OP--move out--visit the smoking parents in restaurants that don't allow smoking. Ditch the fiance' if he won't quit with you--Vivienne's right--you'll fight endlessly about it if you quit and he doesn't.
And good luck!