Sometimes you realize that a deal breaker you had was unrealistic. Perfect example in your post about weed. Thanks to growing up with a drug addicted brother, I wanted nothing to do with any man that had ever even so much as smoked weed much less anything else. However, I grew up and matured and realized most of my friends have at least smoked it at one point in their lives if not still doing it. So, I've since changed that deal breaker to make it more realistic.
I still don't have any interest in anyone who does any drugs (weed included). No smoking anything. I'm not saying that I mean they can't ever have done anything in the past. The point being PAST. I've tried being more tolerant of smoking or smoking cigars but it just doesn't work for me. As far as drinking goes....maybe 1-2 once in awhile....as in weeks or months go by without. In my experience, it's been completely realistic. If I'm not going to be ok with my children doing something, then I'm not going to be ok with having adults around them that are modeling such behavior.
A brother who wants to get high all the time and ignoring his White girlfriend is a real deal breaker. Especially one that does not get high with her.