When Marci Needle and her husband began to contemplate divorce in June, they thought they had enough money to go their separate ways. They owned a million-dollar home in Atlanta and another in Jacksonville, Florida, as well as investment properties. Now the market for both houses has crashed, and the couple are left arguing about whether the homes are worth what they owe on them, and whether there are any assets left to divide, Ms. Needle said. "We're really trying very hard to be amicable, but it puts a strain on us," said Ms. Needle, the friction audible in her...