Marriage as the Designer planned?

some time ago I heard that the divorce rate in our country was highest among evangelical Christians than any other group - including unbelievers. I don't know if that's true or not but I doubt anyone will argue with the fact that divorce is as large a problem among church folk as anyone. Dr. Weaver in his seminar "Designer Marriage" has stated "God has no design for marriage failure. His plan for taking two totally separate individuals and creating out of their bond one complete individual is a marvel of His work and power. Attempting to perform the same action without His miracle - working perfection, leads only to discouragement, despair and dissolution (usually in that order)." Question(s) - do you believe this to be true? Why? If so, why do so many of His folk fail at it? (beyond the obvious answer of disobedience). Among all the challenges every marriage faces, what is the one area that could, if left unaddressed, blow up and doom your marriage?