You have a lot of wisdom about your situation, Penguin.
Live is right, being in a relationship with a pothead is very much the same as being with an alcoholic. The drug comes first.
I have learned the hard way that no contact really is the only way to go. When you start to put the fantasy before the reality, or when one little text seems like it will be harmless, or one simple phone call...stop and rethink it. Come here, call a friend or a family member, go through a mental checklist of everything wrong with the relationship, go for a walk or a run....anything to prevent yourself from breaking no contact. You will be glad you stopped yourself.
You are absolutely doing the right thing...for yourself and for him. It's time to enjoy your life the way you like to live it.