If anything threatens the institution of marriage it's a 50% divorce rate. My father, for reasons I don't understand, transitioned from a Reagan-hating Democrat to a raging born-again Fundamentalist over the last decade. He had some choice things to say during the 2004 elections, at which time Oregon had a gay marriage ban on the ballot. I asked him how exactly he and my mother didn't make a mockery of marriage themselves when they divorced in 1993. He was unable to answer my question.
I love my mother and father very much, and bear no ill will toward them for the divorce, but I would rather put a bullet in my own head than divorce my wife, if it ever came to that.
Here in the USA we have idiots (typically those living in megacities) who, without sarcasm, say things like "I'm so excited that my first marriage will be in two weeks!" (real quote from some idiot I know)