I took it upon myself that this is MY responsibility to get my son to school and we had a great morning.
That makes me smile. I'm SO GLAD you and your son had a great morning. Just because your husband is screwing up his life doesn't mean he gets to screw up the lives of his children and his wife as well.
I can spend my life being resentful and angry towards my ex for being a drug addict, an absent father, and just a selfish jerk in general. Or not. I'd rather take responsibility for the choices I have made in my life, work hard to be the best person I can be and put all my efforts into raising happy well-adjusted children. No matter what their father does.
I think that's what they call DETACHMENT.