Once you lose that salary, the woman has less incentive to put up with a marriage she is unhappy with. If people will marry someone just for the money, I don't find it much of a stretch to assume they will stick together as long as the funds keep flowing.
Consider a couple that is living together. They might be unhappy, but bearing it anyway because they have a lease and moving out and separating all your stuff is a pain in the ass. However, once that lease comes up for renewal, suddenly the burden of breaking up isn't so heavy, which might be just enough to make it happen.
What I was proposing for marriages->jobs is analogous.
This behavior just reminds me of the concept of a philosophical zombie. They seem to make the choice not through conscious thought but through unconscious programming.