Each divorce is different.
Normally you add up all the assets you own between you (House, saving, pensions, other valuables etc) then divide them between you both.
It may not be a 50 / 50 split, this can depend on all sorts of things (custody of children, their ages, length of marriage etc).
It may be, for example, that if there are young children and you get custody YOU keep the house, and he keeps his pension.
If that is agreed then you would have no claim on his pension in the future. Of course, he would have no claim on the house either.
Or maybe HE would get custody of any children and be allowed to live in the house till they left home, and YOU would have to move out.
The house would then be sold when the children left home, and you may only get your "half" then. In this situation he may also be allowed to keep all his pension.
As I said, each situation is different.