Hey Mammy
I think it’s worth remembering that he left you whilst he was in the midst of addiction. His thoughts and actions whilst being an addict are not the same as they would be if he wasn’t using… so as hurtful as it has been for you, reading into what he’s chosen to do whilst actively, seriously using cocaine is perhaps not a great reflection of how he truly feels underneath everything.
It could be the case that he thought he was saving you and the children from being exposed to his addiction. Or maybe he found it too distressing being around you guys whilst he knew he was in such a state… or some other variation of that. If he ever gets clean then that’s a conversation you could have with him. In the meantime, try to be kind to yourself and don’t second guess his actions. It will only pull you down and make you feel bad about yourself when you have nothing to feel bad about. You are the strong one, holding the fort and taking care of your children.