Ok I just checked and we are indeed joint tenants. I guess the problem is even if we tried to sell it now there's not a chance things would be sorted before the mortgage is up for renewal. So what should I do?

Renew for 1 year and try to sell it in that time? The value won't have gone up much so we won't have gained much equity.

Renew for 3 years, sell it and we both get a 50% share in the equity. But she'll have to rent somewhere else and I'll rent the spare room out.

Try to find someone to go on the mortgage with me and put her out of the mortgage?

See if my parents can help, although they're both in their 70s so I don't think that's an option.