Well, it was an interesting evening and no mistake.
Although it shouldn't have taken something like this to draw us back together, but it worked.
The short answer is that he panicked. He mistook my sobs of desperation on the phone for anger, and thought he was going to be yelled and shouted at when he returned home, so he pretended it wasn't happening.
When he finally got home (after giving the wrong address to the taxi driver and having to walk a mile home) he was very very sorry. He thought I was just giving him a hard time for being out - not that I was worried for his life and had called the police because I thought he might have been run over or mugged. As soon as he realised this he was really remorseful and apologetic of what he put me through.
We had a long (hour+) talk about what was going on with the move, with his behaviour, with all the other stresses in our life. Because of the timescales, the urgency and the long time we'd been separated, we hadn't had a proper talk about the specifics of the non-logistical aspects of the move - the stresses of his work, the stresses of single parenting on top of moving our family and our possessions 12,000 miles.
Neither of us had realised how close the other was to breaking point - we were putting up such a good front to eachother and to other people, that we thought the other was coping fine.
He talked to me in a way that he's never done before, and told me things that I never realised were going on. Eye opening things that changed my opinion of him for the better
The boundaries that we had before have been reconfirmed, and we are more resolute about what our intentions are. He felt he was letting his friends down by not going out when they asked him, when in fact it should have been the other way round - he spends extra time with his friends when they need help, not him. At the end of the day, because it has been all so messed up with him working away for so long, it seemed the obvious way to de-stress after a very hard day - after all, that's what he did when I wasn't there, and he didn't want to get aggro from me after a hard day's work for both of us.
When he arrived back in the UK for 5 days before we all flew out together he found it really hard. He felt excluded and redundant, and he said I made him feel like he wasn't necessary, and just got in the way. This was true to some extent - I'd had to manage everything to the nth degree just to make it work and get us on the plane on time, and every time he tried to help, he just made it worse. Therefore he thought that when we came over here he was still redundant and just got in the way, which was very much NOT the case now that we were basically winging it. He has always had quite low self esteem
So, was he being selfish? Yes of course, but I understand his reasons for it a lot more, and maybe I would have done the same in a similar situation.
As for the "other woman", well I don't trust her as far as I could throw her - she seems manipulative and predatory, although I say that from a very brief meeting. DH has agreed that the intensity of their friendship was inappropriate, and also unprofessional. He has also said that her flatmates and her circle of friends are a bad influence on him, and has said he's going to distance himself from them, while staying cordial with her. I trust DH with her, even though I don't trust her.
Sorry for the long post - I think I just needed to put it all in writing.