We moved abroad for partly financial reasons, partly quality of life reasons, and partly chasing a dream.
It isn't always cheaper to live abroad but this depends what you end up doing, how many financial obligations you have, and what day to day expectations you have.
You have to think that you could be arriving in a new society at the bottom rung and end up struggling in much the same way as you are now. Investing in a rental property in the UK can help you make your money work for you after moving, so that you know you always have some money coming to help you get started and an investment in the UK to fall back on if you move back or need to cash it in.
It is very difficult to be away from family and friends (those who know you well and know how to support you), especially when times are tough. And for me the long winters have been difficult, although I think that's a case of lack of sunshine bringing me down! I know it isn't the same but skype has been a life saver for me. I have really hated missing out on seeing my nephew and my friends' children growing up - skype doesn't help there .
This is hypothetical, of course, but also think about whether you are strong enough as a couple to cope with massive changes to your lives. If the UK stress is already causing problems between you, moving abroad could multipy that pressure many times over especially in the short term, until you are settled. You have to have the same dreams. If one of you has even the slightest reservation and the other one is keen, that tiny difference could open in to a chasm when times are hard. And if you are 'alone' in a new place how will you cope if you are having problems between each other. You will need to be each other's only allies - I say that bit from experience!