I'm upset at my boyfriend for smoking in the bedroom
Why are you upset that he smokes in the bedroom?
Because I don't like the smell.
It's understandable that you are upset about your boyfriend smoking in the bedroom. Talk to him about this behavior and let him know it is unacceptable.
If I talk to him about it do you think that he will stop?
Hopefully he does, because smoking inside of a home while knowing that another person doesn't like it is inconsiderate. Talking to your boyfriend about this will let him know how serious you are about it.