OK, best get a pot of tea and packet of biscuits before you start reading...
Just spotted this thread, and like hogshead, cannot understand why it is so important to "go back home" when there's the whole world to explore.
It's such a shame he cannot bear to share his parents with you, if visiting home is the only travel that seems to be possible up to now.
As for your parents and him expecting you to resolve issues with your mother, I suppose he cannot "get" that it may never happen (given your father doesn't seem inclined to rebel, perhaps for a quiet life, that relationship is going to stay "on the rocks" for the foreseeable future, perhaps, unfortunately).
How long before this overseas position is likely ? Just curious because you might want to give him an ultimatum, if it's getting you to "exploding point", along the lines of "If you don't think I can be with you when visiting your parents, do you really think we have a future, or do you only think about your own feelings and plans?"
It might give him sufficient shock to finally understand how selfish he is being, that you don't want to be forced to visit your parents, and that as a couple you should be able to stay with either set of parents - it seems that as far as meeting each others parents, everything goes well, but staying with them is something he has ruled out.
Even if he acquiesces I'd still suggest you keep a few trump cards up your sleeve, in case, as GeekOfTheWeek has suggested, you decide to "Get rid".
Going abroad without a position to take up will make you dependent to some extent (you don't want to waste savings that have taken time to accrue, and it's not clear whether this is long-haul or short-haul, whether languages would be needed, or whether you'd be able to get a job there legally, just to avoid boredom from endless 'sightseeing' or shopping!
As for your academic career, would a break be sensible ? Presumably there'd be no major harm unless you got too far away from current work in your field. I asked about the timing of this overseas opportunity, because it would clearly benefit the overseas body if they had early notice they need not worry about relocating you too...
Though of course living in the UK, separate from your parents, without any income, and perhaps ineligible for benefits as you have savings, going with him is perhaps the lesser of two evils (or am I being too optimistic - do you foresee a life of hell if things don't change radically ?)
If the financial situation for academics is likely to get harder for the next few years, then maybe you should seek a complete change in your life - become a professional house-sitter, or a companion, for a year or two, and let this selfish so-and-so buzz off abroad. I suppose a companion would not necessarily be suitable - was thinking on the lines of somewhere to live, keep up to date via the internet with both academic work and opportunities for a new position, without wasting all your savings...
Hope you didn't get too bored with my ramblings... and good luck whatever you decide to do...