The case would be that while you did all the company work your spouse was doing, eg, childcare that freed you up to make the money. Historically a wife might well be doing the books or PAing or running networking events all without a salary or official job title and might reasonably expect compensation for that work. I don't think current marriage law is very good at understanding the sort of couple who both contribute both financially and otherwise in equal measure, neither giving up income to further the other's earning power.

There are other aspects to marriage law though that you might want, some tax changes, next of kin status, intestacy law. And divorce ought to cover the future care of children.