Today is my 18th wedding anniversary. My wife and I were married young, after meeting each other online and a very brief courtship. As I look back, I’m pretty sure we were nuts. There are a handful of factors whose presence make a marriage statistically more likely to succeed or fail over the long term. My wife and I managed to come up on the wrong side of an awful lot of the divorce indicators. We didn’t know each other well, we argued a lot, we lacked financial stability (I lost my job the week we got married), we were up to our eyes in student loan debt, we were too young, too immature, and...