How much should my future ex get from the sale of the house?

PadreM

PS It COULD be argued (not convincingly) that as (as I see it) he has agreed 12.5% equity in the house and is now renting, you pay 12.5% of his reasonable rent.  However, not only is this a petty sum in rent, as he's not losing his equity (but IS forgoing it for some years - and losing a small sum of interest on that) it's not 'costing' him anything.  Indeed, the fact that you are keeping the house on, when it would otherwise have to be sold, means he enjoys a relatively good return on his investment given house price inflation (though not guaranteed).

In this case, as he's being decent, I'd be decent and pay any removal costs or, if you can afford it, his deposit or first month's rent, in recognition that he's allowed you generous time to recover his equity.

JaneTheCat

Thanks to all who have answered - interesting, two totally different points of view seemingly shown in the responses, from 50:50 equity, to a % of total sale price.

Either way would change how much was shared - interesting. 

I thank you all for your input - there is a lot for us both to discuss. J x