Why do you think Priests and Nuns aren't married? The Bible, or the "Christian Handbook", clearly states that 'Marriage' is intended for people who are sexually 'loose' and though not a sin, God prefers we NOT get married. Its as clear in the Bible as any other Biblical "fact" Conservatives throwback to when trying to prove a point.
As to marriage declining as social influence of O. Religion declines ... no proof one has to do with the other. Again, people use God to ease the 'blow' when dealing with things. Perhaps your marriage is good BECAUSE of God, but for me, my marriage is good because I put in 100% and my husband puts in 100%. Not because "god is blessing" my marriage. Why would my marriage be more worthy of blessings than one where a woman is getting the living crap beat out of her? And, perhaps your marriage failed because it "wasn't in Gods plan" or because "Satan" had a stronghold ... but for me, it would be because one of us stopped giving 100% to the marriage. For some people, they can do nothing without God... but for me, I can do everything without him. I think the more productive solution for humans would be to stop using, blaming and crediting God for everything and take some personal responsibility over our lives.