How are things now Nessa?
It sounds awful for you. Objectively though – your friends are not your friends if they judge you. Your husband is ill – not horrid. When we are anaesthetised we do strange things – behave out of character – see the alcohol as the cause of your pain, not your husband. Try to stay strong.
Maybe the argument was a lever for him to go off and do what he wanted to at that time (drink? see the other woman? or just escape the guilt of confronting what he is struggling with). Impossible to say , so be clear and objective. Set boundaries and don’t shift from them. If you love him, tell him so, but also tell him what he must do to sort out the problems.
If the children are young, then keep them out of it as much as you can.
Sending you good wishes…..