If my partner made no contribution...

Unfortunately:

a) the informal agreement will almost certainly not help much. The financial position will be re-assessed based on today's financial position and today's financial needs.

b) the law has a very vague notion of non-financial contribution. People who never lifted a finger to do housework dont seem to be any worse off in their "contribution rating" than people who earn all the money and do all the housework. It seems (to me) that it is just accepted by the courts that people married that long must have contributed equally in some way or other. I would be interested if anyone has experience to show that a court really did analyse in detail exactly how much contribution (housework etc) someone made and adjusted the financial order accordingly. As far as I know the parties needs seem to trump most other factors - especially contribution. ie the court basis the split very largely on what it feels are the needs of the two parties - not on what contribution they made (again I am talking about a long marriage here).