I have the same problem as you - bf doesn't like the fact that I smoke, but I live with him so its hard to hide it and I'm not able to smoke as much as I'd like.
The safest method is for me to smoke outside then spray fabreeze on my clothes, brush my teeth, and spray my hair with something. I used to smoke inside when i knew he wouldn't be home for several hours and spray the room with fabreeze, but I've had problems getting rid of the smell a couple times and he noticed right away. Eventually he will find out if you do it enough times - do you live together?