I always felt disgusted with my ex when he was in that state. Then I realized that truly, I was disgusted with myself because I was allowing myself to be in a relationship with someone who acted that way. I had no self-respect. Expecting my ex to change because that's what I wanted was ridiculous. He was a drug addict doing what drug addicts do. If I wanted change, it was going to have to come from me.
Have you thought about how long you are willing to expose you and your children to his lifestyle? Maybe if you work on a plan to change your life you'll feel better.
Do you know what they say about resentments? It's like drinking poison, and expecting someone else to die.
I know that was true for me because once I took responsibility for my choice to be in an unhappy unfulfilling relationship, and stopped trying to rely on an addict to be anything other than a drug addict, I became much less resentful and much happier. Even though he was still a slug on the couch, my future happiness no longer depended on him being something other than that.