You're conflating two things:
- Accepting you
- AND -
- Accepting everything you do
Clearly, your boyfriend is accepting you. He still wants to be around you and has made it clear that while he does not enjoy your weedsmoking,
overall he is attracted to you. For him to accept you should not require that he agree with everything you do. I can see how you have a problem if he forces you to change your habits, but even that by itself is not extraordinary, since people do have each other change a few things when they date, its part of a relationship.
Here's what it boils down, your boy is stuck-up / goody-goody and he doesn't like smoking weed. He tried it once, not to send a mixed message, but to try to understand what you like about smoking weed and to be a little bit closer to you, in the end, he experimented and came to the conclusion that it wasn't for him. Why should you try and force him to change that? You guys disagree: fine. Live with it.