My partner smokes weed.. and I hate it

So I've never been into the whole drugs thing and my partner has smoked weed since he was about 11 years old and is now 30. It drives me completely nuts. Why? Because it is illegal and I think it stinks. Above all, while he works full time and gets paid a reasonable amount of money, he can't really afford it and often asks me for money. He's a good guy and I love him but we had an argument the other day because he said last weekend he would stop and then went and bought some on Monday. In fairness, I gave him a disgusted look and walked off. I tried to talk to him about it and he got a bit shitty, I told him that he has $60 in his account and chooses to spend his last dollars on a 50 bag so now has $10 until next week and I knew he would come and ask me for money. Well I offered him to take my card today to buy lunch cause we didn't have any and I checked my Internet banking and he has gone and filled up his truck and bought himself food and coffee. Am I wrong to be annoyed? Does it seem like I am supporting this habit? I find it hard to say no and we are supposed to be a team but I feel this is ridiculous. You are 30 years old, can't really afford it and aren't motivated to do things you should be prioritizing. On top of that he sleeps most night on the couch falling asleep in front of the TV. 😑