I think you overreacted a little bit. The guy wasn't snorting coke; marijuana is a fairly mild drug. SWAT teams are not going to break down your door because your guitarist is a pothead. He wasn't pressuring you, and he wasn't "disrespecting" you any more than if he had opened a beer midway through rehearsal. I don't see what your wife and kids have to do with anything. That said: If you don't feel comfortable playing with him, then you are fully entitled to change the situation. I think you'd be better off asking him not to fire up during rehearsals and performances.