Few things really, pulling your OP apart and taking it bit by bit:
My husband was due to be going out tonight ( a regular fortnightly thing) and was out last night too. He works from home and generally helps with bath/ bedtime of the kids. But tonight he had a work call that went on til 7.25 so I did the bath etc. he just came upstairs in time for stories so I let him take over.
helping with the kids is saying that it's not his responsibilty. as is babysitting You have a 21 yo, they can babysit, your H would be being a parent to his children
A couple of minutes later he'd put my son in his cot and said goodnight having read one small board book - usually does a few books. At which point I complained about this, not shouting or swearing ( obviously) but I was annoyed. He was very indignant telling me his work had gone over and he was supposed to be going out at 7.35.
If he is going out, one board book is FINE. why wouldn't it be. If he is going out, and you thought more books were required, you could step right back in. You have to leave him to parent in the way that he wants to, micromanaging is ridiculous and guaranteed to annoy even the most passive of partners.
I headed down the stairs saying why is it always me that picks up the slack just because he's going out and that he wasn't here last night to help at bedtime either.
Here you were unreasonable IMO, he went out last night and the night before and otherwise does do his bit with the bedtimes. You too could go out, but are choosing not to. MAKE THAT A PRIORITY FOR YOU TO CHANGE BTW
He said that's my choice that i don't go out much ...
Fair enough. He has a point here - do something about that! :)
and as I went down the stairs he flew down the stairs after me - kind of chasing me.
Here is where it goes completely wrong and wonky.
I don't think this is on really, I felt quite scared.
He has no right to do this to you - that's abusive and deeply dysfunctional
He then lay on the bed for the next 20 mins until I came back up ( my son was calling out) I was in the bathroom with him when H came in and said " thanks for ruining my night" and inferring that I'd thrown a spanner in the works to scupper his night out!
He has no right to do this to you - he's blaming you for something that HE is creating (by not geting himself ready to go out) AND also punishing YOUR child because he's angry at you.
I told him that his threatening behaviour wasn't on and he said no it's not ideal but why do you always do it ( complain basically)
He has no right to do this to you - he is blaming you for his scary behaviour AND neglecting your child calling out for him
I asked him does he not expect me to say something if I'm unhappy and he said " no not really" He then went out after telling me that he wouldn't be home til tomorrow night or Saturday morning
He has no right to do this to you - punishing you AND your DC.
What you do now is to tell him to STAY out until he stops trying to control you and your family. he is setting your DC a terrible example.