'Yes, marry for money': A Harvard-trained economist shares the surprising financial benefits of marriage

Valentine's Day is almost here, and is all the rage. According to the Wedding , there will be some 2.5 million weddings this year — the most since 1984.

As an , I'm all for it: Marriage beats partnering long-term. I'm no expert>Marrying for isn't a bad thing

I'm not claiming that money is the>Marriage can mean important Social benefits

On top of short-term financial benefits of marrying, like the implicit joining of resources, there are long-term benefits, as well.

First, after just nine months, you're eligible to collect widow(er) Social Security benefits. Plus, after>Get married, but always assume you'll get divorced

Marriage can also benefit your long-term standard of living, albeit to a highly imperfect and uncertain extent, if you're awarded alimony in divorce.

An estimated 41% of all first marriages will end in divorce or separation, according to data from -based law firm Wilkinson & Finkbeiner. Some 60% of second marriages go south, while 73% of third marriages will start with "forever" and end with "sayonara."

Yet, we all marry convinced we'll . Economists call this phenomenon "irrational expectations" — when people collectively believe in something they know is collectively false.

But wishful thinking about marriage comes at an awful price. Many marriages end in exorbitantly costly divorce war, with forced to take sides and family ties shredded forever.

Maybe it's time to reset our idea of marriage from a lifetime partnership to a temporary arrangement that should be celebrated for lasting as long as it does, not lamented for coming apart.

Put a prenup on it

Take the case of hypothetical Sally, who wants her spouse-to-be, Sam, to stay with the kids while she pursues her lifetime dream of being a contractor. Sally is a go-getter. Her plan is to borrow $1 million, construct and sell a dream house, and use it to showcase her talents.

The problem, from Sam's perspective, is that fulfilling Sally's dream means giving up his career. Plus, if they split and the house sells for $500,000, Sam will get stuck with $250,000 in "their" debt.

Moreover, Sally wants to live in Texas, which is far less generous in providing alimony than, say, Massachusetts. So, if Sally's career takes off, but she takes off with the tile subcontractor, Sam will reap precious little from his investment.

If Sally and Sam marry without resolving this potential conflict, Sam may get cold feet and file for divorce before he co-signs the construction loan. But what if they sign a prenup that assigns, upon divorce, all construction debts to Sally, but provides Sam half the profits if Sally's company succeeds for, say, 20 years?

This lets Sally take her shot while protecting Sam.

Despite the clear benefit of prenups, not signing one is a huge mistake that many people make. Whatever financial concerns would be addressed in a prenup will inevitably arise once you get married.

It's far better to negotiate in advance how things will be settled than have one party feel they have, in getting married, lost bargaining power in making financial decisions that could damage them in the context of divorce.

My advice? When you kneel down and propose, take two things out of your pocket – a sparkling diamond ring and a leather-bound prenup, which will surely be worth far more than its weight in gold.