Thank you all for your advice.

inarut: He's very resistant to going to therapy ("I don't have time" is the usual excuse) although I think it would help give him tools to manage the stress. He might be more open to medication, something mild just to get through this period. I can suggest it to him as I went on a short course only once to help get through a death in the family. I try quite hard to suggest ways of at least changes his mind frame even if he cannot change his situation (if anyone's ever read Viktor Frankl's "Man's Search for Meaning") but I think he's just too tired and emotionally drained to spend energy on thinking about it.

bobblington: Very, very fortunately I'm going home for my sister's wedding and I've taken the chance to book a short holiday for us. He's really looking forward to it. I banned him from bringing his laptop and he has to keep his phone switched off. I think this is probably the best possible thing for us right now and hopefully we can spend some time talking and figuring out how we move forward as a couple.

J27: He is absolutely a workaholic, he always has been. He doesn't switch off. Even his hobbies would count as work to everyone else. Your story is very hard to read. These stories don't always have a happy ending and sometimes you can pour your life and soul into another person and it ends up amounting to nothing. I'm really sorry it worked out that way for you. I'm very worried about having to move back because it will essentially destroy my chosen career. It's the kind of situation that has no win-win outcome. I'm really scared of my husband changing and turning into someone I didn't marry. I want to help him but you're absolutely right, no-one can truly help anyone really, they have to want to get better. He seems so stubborn and he just won't listen to anything I say but I remember being exactly the same way. I would have tried to deck anyone who told me "you need to get some exercise" even though it actually would have helped. I guess I can't force him to do anything but only give gentle suggestions and just be there for him when he needs me.