Ex would tell me he that he "had to go and do something" and walk out of the door, never any discussion. It didn't matter how many times I explaine that I didn't want him to ask permission, but that it was part of a loving relationship to check that I would be OK staying in looking after our children on my own, that I didn't have plans for me, that essentially he was demanding I look after our kids with no option by walking out the door, he never once changed.
He would sometimes ring and say he'd be home in half an hour, this was always a lie, he often was not anywhere it was possible to be home in half an hour from, or he'd say he just had to help some friend in need, whatever. "half an hour always meant "gone until at least the wee small hours". I stopped answering the phone, becasue I knew he was doing a big "performance" to his mates about how under the thumb he was having to check in with me, and his words were always lies.
sometimes it was drugs, sometimes it was just more alcohol, no responsibility, basically it was just doing whatever he wanted right then, utter and complete self-centredness, and he got a kick out of getting away with it, like a teenager would in gettign to convince their parent it was ok to stay out all night: he acted like this no matter what I said or did or didn't say or didn't do, and in fact acted like this when at the end I was glad he was staying out because it meant I didn't have to deal with his abuse.