What do you call her again?

The limbo of my marriage leaves me asking, what do you call a spouse who is no longer a spouse, but to whom you are legally married? Here's a list, but none of them really does the situation justice.

The mother of my child
My Ex
My parenting partner
The sponsor of my graduation education
Someone I used to know
Someone I used to be partners with
My separatee
The person I'm too entangled with to be independent
My future ex
My financial entanglee

This has happened to other people. Why isn't there a word for it? Any suggestions out there? This whole thing is going to take a while, so I need a word...