Personally, i have no problem with it, as long as you feel you can trust that he will not try other things, and stats over drinking to get something better than the pot high. It seems to me that he know when he should be doing it, and him being successful is all the more better. I feel it is hard to deal with smoking, and doing other things , like drinking which is far more dangerous than marijuana, but i feel that if you don't want to use the drug, that is your choice, this shouldn't effect the way he feels about you or the way you feel about him that he does.