His behaviour in staying out is just one part of a pattern of behaviours. Its not an isolated thing.
The sooner you are apart the better, and that message around 5am was grim. A totally shit way to say its over, which is how it sounded.
First thing Monday call cms to open a case, and speak immediately to benefits to get a claim underway, as, even if you don't need it, at least you can cancel it, but the claim will only offer any benefit from the day it is triggered by your call.
If you do nothing else, just call and register with both.
Sadly, it doesn't sound like your relationship is one that will, or should, last.
Its better you know this and act on it now, as some live this life all their lives, and is destroys those subjected to it across many years.
To walk away from your partner, without explanation, discussion, or even a late night text to share your intent, is what it is, breaking partnership trust and respect.
He probably feels in power, that once he's out, you can't leave, because he knows you wouldn't leave the dc you love. He forced you to be housebound through the night. You couldn't even nip out for a bottle of wine, etc.
Thats arsehole behaviour and showing no love or care for you, never mind the dc!