A therapist? Someone safe to offload to? Depending on where you live it might've better to Skype one in the U.K. - even near where you want to return to. I know it costs, but if you have a private account could you do it without him knowing?
Are you married? Could you also keep a record of things and send to someone (parents, a friend) for safe keeping? So if he hits you and there's a mark, send a photo with details of how it happened? Then you could have some trail of the physical abuse. You could also keep a diary (start a new email account) of the other abuse?
It wouldn't stop anything and you'd need to be SUPER careful how you go about it, but it might feel like you're doing something to build up for your future in terms of access to kids in the future. Maybe speak to lawyer about the use of all that first.
I'm just brain storming really.
If you're not in the uk and will return, and I'm guessing his income is high so technically money shouldn't be an issue, could do something like an OU course as an "investment" in your getting back to work one day (unless he doesn't want you to do it'd be a dangerous issue), or for fun (if that idea could work)? That way you'd have something moving your life forward and to focus on too that might take the edge off the extreme stress you're going to be under.
And I'm not telling you to leave him now, because I understand your situation. Living abroad, especially when you're financially reliant on your partner is more vulnerable than most people can imagine. My situation has been similar (different abuse) and it's unimaginable to many on this site that you can't call Woman's Aid or move back to your parents' temporarily. And often you're living bing somewhere where social and school life involves a lot of his colleagues/their partners so it can be like a gossipy village. Hope that's not your situation OP, but I've been there and before that (when I knew I would never be in that situation) seen other people in it.