I doubt the divorce rate in the Bible Belt has to do as much with religion as it does the general comparative ignorant backwardness of people living there in general. If anything, I would bet that without religion the divorce rate, crime rate, and generalized demoralization of people there, generally, would be even worse.
Fairly broad generalizations based on stereotypes and your already hostile disposition towards religious conservatives.
A perhaps more valid and viable dynamic is that people in the Bible Belt tend to marry rather young when compared to their blue state urban counterparts, and therefore make impetuous marriage decisions. People who marry their high school sweethearts are more vulnerable to divorce, regardless of religion.
People who grow up in urban areas tend to place more of a priority on furthering their education and careers, which exposes them to more dating opportunities and delays marriage commitments until they are at an age and maturity to make such a decision. That, and the urban/career 20 something is perhaps more open to the concept of living with someone prior to marriage to test the waters.
For the record, the same dynamic exists in the rural areas of many blue states, not just the Bible belt.