My husband had done things like this many several times, and there has always been a plausible but infuriating explanation. (and no - he isn't an alcoholic, and never has been - just very 'sociable' and can't drag himself away from the company once he gets going, and so those kind of comments are alarmist and not remotely helpful.)
I have been married a very, very, very long time now, to a man who is essentially good and lovely and decent, but who gets a bit giddy like a child when the occasional prospect of a good night is concerned. 
But I have been exactly where you were on Thursday night OP, stuck at home with a baby in bed, going out of my mind with worry, either before mobile phones were common, or with a DH who had a flat battery or no signal. To say I went to hell and back and could have KILLED him once he finally turned up is an understatement. I've done my fair share of calling cab companies and A&E units and police stations too.
I have learnt that he is an intelligent grown man, stupid sometimes, yes, and if he gets into stupid situations due to being drunk then that is his problem and he can get himself out of them. I have learnt to ignore him, and get a good night's sleep. I know it's not easy - even after all these years I have a body clock which is programmed to wake me up at the time his last train would usually get him home - so if he is not on it, I know. but my days of prowling the house and worrying are over. I just get very irritated and go back to sleep now.
In my time I have:
had the police walk along railway tracks to rescue him from a locked train in the sidings at 3am because he fell asleep and no member of staff found him. By the time he woke up he could not get out and it was pitch blck and he didn't know where he was. This was pre-mobile phone days so it was only detective work between myself and the police that we worked out where he was at all. He had to walk about a mile along the sidings with the police back to the railway station, then I had to get the baby out of bed and drive to the station about 10 miles away to pick him up. Happy? You betcha.
I've had police cars and ambulances going up and down Oxford Street looking for him because he'd collapsed in a phone box having had a massive internal haemorrage (just one of those weird things - he had very bad bleeding piles and bowel problems partly due to food intolerances and partly due to a very stressful job - he could not have predicted it, but I'm sure the booze did not help) and he ended up in hospital having a blood transfusion (ok, not his fault , but the fact he was too pissed to tell me exactly where he was while he was bleeding pints of blood into his shoes made the whole thing a tad more fraught)
And I've phoned the police and A&E because he once rang me to say from a cab to say he was about 5 miles from home at about 10.30 pm and by 3am he still wasn't there. He'd got the cab to drop him on the corner so I didn't hear it arrive, (because he didn't want to wake me - he knows I am a very light sleeper) and as he was walking towards the house he saw our neighbours having a drink in their garden with some friends across the road. They invited him in, his phone went dead, and the fucking twat just assumed I'd be asleep and so 'forgot' to nip indoors and tell me. And the rest, as they say, is history.
OP, if your DH likes a party you have two choices. You either give him an ultimatum about the ground rules now, and threaten to leave if he doesn't comply, OR: you learn to disengage and let him take care of himself. Personally I'd recommend going for option 1, but if he is a good and reliable man in all other ways then option 2 can work. It might take 10 years to get the hang of it, but eventually it will work.
22 years on I am testament to that. Although reading this back makes me wonder if I am aware that I must sound like some kind of idiot.