Thanks for all the replies and continued discussion. There is a lot to quote and correct in lots of posts but having just got back from work now is not the time. There is more details I can give that I didn't really want to post but may have too. I shoukd have time before work later to reply.
@coolsurfer i don't play wow. Not for at least a year. I may have loaded it and played for an hour since but that's it. I don't play video games anymore not for a long time. Overtime is not an option a better paid job is what I have been trying to get since I was made redundant in 2015. I am vaping to help quit smoking. My repayment mortgage is over £1000 per month. Hence the interest only.
I can see why you're backed into a corner. That's a pretty insane amount to be paying for a mortgage on a house that's only worth maybe 140k/150k.
What are your plans in ~10 years when the mortgage is up and you need to pay off the full balance?
I really think you need to seek financial advise as well as legal advice about your situation. A solicitor will only be able to advise you what your ex can and can't do wrt to selling the house. A FA will be able to look at what's possible for you to do with the mortgage in the term left etc.