Husband wont stop smoking!?

Smurf
Ive been asking my husband for 4 years now to quit smoking! He keeps giving me the run around "ok" "i will" "ill try" blah blah blah. I was really lenient with it at first. i know its hard to quit because i used to smoke. But now its at the point where im pissed. Though everytime i say something i get "you dont even care that im trying i havent been smoking as much and you dont even see it!" or "this pack lasted me all week and youre still mad!" yes i see it! but yes im still mad! I cant be proud anymore that he gave up 1 cigarette a week when ive been asking him to quit for 4 years. Now that im pregnant it brings me to tears because 1. ive been asking for SO long 2. he swore when i got pregnant hed quit and 3. the smell of smoke makes me sick to my stomach. He thinks just cause he goes outside its ok. Hello!? You smell like an ash tray all day when you come back inside and your breath REEKS! Every now and then when he goes to smoke i ask "why cant you just not smoke right now?" and he never just says youre right. Its like he'll "try" to quit 1 week out of the month just to shut me up. What do i do about this?