How to buy me out ?

RAS

Legally, you are entitled to half the joint assets, so half the house, half of the two pensions combined etc and half of any savings.

Since you are joint tenants, you need to go and see a solicitor urgently. If you die tomorrow, your ex becomes the sole tenant and gets everything, possibly including a widow(er)'s pension if your scheme provides one.

Do you want that?

Obviously if he keels over on the golf course, you get the same benefits but it may be safer to sever the tenancy on the house, which ensures you own 50% outright. 

You can divorce for very little cost, but it is the financial settlement that often results in legal fees. Even then it looks like you may have to force a sale.

It's worth looking at wikivorce which has some very good guides and folk who are in the same situation.