I've seen elsewhere that financial troubles often herald divorce. If the only marriages that can last are ones where someone's making a premium, then of course you'll see one.
In this case, explanations for A and C being correlated without A causing C are strongly related to explanations for why A and B might be correlated without A causing B. (E.g., people who get married are predisposed to be successful.) Evidence, which necessarily can't be in the form of a randomized controlled experiment and yet can still be very strong, that A in fact causes B greatly reduces ones belief that A might not be causing C. My previous comment was asking whether you would defend alternatives that I find to be very unlikely, like a hypothetical predisposition for people to both get married and be happy but which is completely independent from the increase in earnings.
Your question doesn't help. For the sake of argument we have granted that marriage causes men to earn more money. And yet, I would still prefer to marry someone who was earning more money (or who had the potential to earn more in the future), all else being equal. This preference doesn't dispute the causation.
http://econlog.econlib.org/archives/2013/03/22_short_argume....