My long term boyfriend has a male friend who I have an uncertain feeling about, and I am seeking some perspective.

For anonymity's sake I will be somewhat vague. The friend has some problematic habits that expose my boyfriend to a lifestyle I do not feel comfortable with. The thing is, some of his other friends / our mutual friends have similar habits but don't give me the same bad feelings that this guy does for some reason. This guy seems a bit pushy with this habit onto my boyfriend in a way I haven't witnessed other friends doing, and also is aware I disapprove of the particulars of this friend's tendencies with the habit.

Now, my boyfriend and this friend also have many shared interests and have gotten quite close in the last few years. I also don't doubt my boyfriends capabilities to stick to his principles and not be influenced into things he doesn't want to do at all. I just feel uncomfortable with this one friend and I also get the vague sense this friend doesn't like me, due to some strange interactions we have (I've been writing this off as just social awkwardness of men, but I cannot shake my uneasy feeling). Again, none of his other friends have ever given me the vibe they secretly dislike me. I've asked my boyfriend if this friend dislikes me, and he reassured me he doesn't and he actually quite likes me. I don't feel convinced and I can't shake this feeling.

What is the best way to handle this? I don't want to be naggy or make my boyfriend feel like I dou t his ability to vett or associate with people of good principle. Should I just keep quiet and wait and see? I obviously am not planning on asking my boyfriend to stop hanging out with this guy or anything like that. I hope I am just being paranoid.

Side note: I think I remember seeing a post on the wiki or something that discussed dealing with your partners friends, but I can't locate it. If someone wants to link it I would very much appreciate it!