My question is how do I explain that I don't think we should try to keep this relationship going? I want a family, but not with a drunk and pothead. Why is this so hard?
I agree with Live you pretty much summed up what you need to say right there.
Or if giving specifics will only lead to nitpicky fighting then keep it even simpler: I am done with this relationship. I just can't do it anymore. I want to break up. It's over. You don't need to explain anymore than that. We all have the right to associate with whom we choose and the right to stop associating with anyone at anytime!
Why is it hard? Well breaking up is hard to do no matter what! But also maybe for 13 years you've been tolerating stuff that actually really bothers you.
I know when I finally accepted the REALITY of my brothers alcoholism I looked back and was like, Oh my God a "together" person wouldn't have put up with even 2 of the 100's of bad situations I put up with. I had allowed them to treat me badly and so it was a little hard to change at first - because it was my habit.
peace-
B