My question involves a foreclosure in the State of: AZ

My boyfriend and I bought a house 3 years ago. I put in $90K, he put in less. Our house is now worth about 40% less than we paid for it. Even putting $90K in we are still underwater by about the same. He doesn't want to pay me to buy me out, but would like the house. I'd like some payment so that I can go find a place to live. If he won't settle with me, can I file for partition without a lawyer? Ultimitly if we do, since we are underwater, that will result in short sale/foreclosure, is that correct?

Do I have any other options?