Well, the two small children are asleep - hardly requiring much looking after. And one would expect the partner to be asleep, too. So not really much to do, no real reason for him to rush back?
Dh used to work away - at one point he went away for a week when I was 39 weeks, with an 18mo and 3yo. She doesn't need him there.
I sleep badly when dh isn't there (if at all) but I know that's my issue, not his.
(Oh, and the bugger did get himself blown up and not get home on time once, so I do have reasons for thinking the worst if he's late... But again, my problem. Not his. And I'd want the same treatment in reverse, not him nagging me about my parental duties when everyone in the household is asleep and there are no parental duties to perform.)
Two of my babies were born in January.
he did drink at the Christmas parties, and was unable to drive. The only time I was mildly miffed was when dd1 developed breathing difficulties in the night when I was 38 weeks with ds1. It was 2am, dh couldn't drive, and we lived 45 minutes from the hospital in a snowstorm (about -20). He held her upright all night and we took her in in the morning.
I mean, really, is it worth getting all miffed just because he's out late and in about 5 weeks you'll have a baby?
I do realise you've said darkly 'not the first time' but without any context as to whether this is a once a week, or he once did the same thing in 1997, it's impossible to comment sensibly n that.
I've done it before as well. About 4 times in the last ten years.