Whilst I understand the need to sever all ties, does he not see the benefits of not selling for 8 months (i.e. all of the financial bonuses you outline)? If not, it may be an idea to ask your mortgage provider to send you an illustration of exactly how much you are due once the mortgage has ended and what you would get if it ended say next week.

Even if that doesn't work, I don't think he'd be able to force you to sell your house without going to court / mediation - and I'd imagine most judges / mediators would suggest that it would be rather silly to sell "early" (especially as by the time you end up with a mediation / court date the mortgage might only have 6 months to go).

maxsteam:

...if you stand firm at such a price.

It sounds like you are wanting to wait 8 months before selling so perhaps you could be flexible with the price around then.

We haven't got a price yet. I would like some arguments to put to him. My gut feeling tells me I should NOT agree to end a mortgage with only that time to run to accrue all the benefits + joint life endowment and bonuses. He's just being adamant because he wants to go to new life.

You could talk to a few estate agents and put the property on the market at the highest price that they come up with. You will both then be happy because you are unlikely to get a sale if you stand firm at such a price.

It sounds like you are wanting to wait 8 months before selling so perhaps you could be flexible with the price around then.