When should a woman be supportive of a man who hits her after leaving a dirty needle in her toddler's bathroom?
Never.
Worrying about how to manage your anger so you can be supportive of an active drug addict-child-and -wife abuser.....this is what the disease does to us: it tricks us into forgetting we are being emotionally and/or physically violated and it tricks us into feeling sorry for the abuser.
You should be consumed with fury. You should not be worrying about his sensitivities and his needs. But his disease has tricked you.
You will need to draw a hard line and hold it. Addicts listen only to what we do.
Hold it for a LONG TIME. I suggest a year minimum separation.
Because he is likely to relapse. And to hit you again. And traumatize your toddler.
Find your fury for your child's protection.
Draw a hard line. It won't be easy. If you isolate with him, rather than go to weekly Al-Anon meetings and to therapy, his addiction will destroy all of you.
There is hope for change. But only if you find the strength to act in a completely new way with him. For that you will need Al-Anon. Isolated, without support, you will have no chance of saving your family from the disease.
It will be the greatest act of love and courage for you to seek help for yourself. Hang on to that fury, it can fuel your determination.
Stay strong. God bless.