Warren Buffett, Melinda Gates and Sheryl Sandberg agree: This is the most important decision you'll ever make

Why the secret to your success is who you marry

In the HBO documentary, "Becoming Warren Buffett," the Oracle of Omaha says that there were "two turning points" in his life: "One when I came out of the womb and one when I met Susie."

"What happened with me would not have happened without her," Buffett said of his first wife, who died in 2004.

In fact, the billionaire says, the biggest decision of your life will be who you choose to marry.

"You want to associate with people who are the kind of person you'd like to be. You'll move in that direction," Buffett said in a conversation with Bill Gates at Columbia University in 2017. "And the most important person by far in that respect is your spouse. I can't overemphasize how important that is."

Warren Buffett (L), chairman and CEO of Berkshire Hathaway, arrives with his first wife Susan at the White House for a state dinner on Feb. 5th, 1998.
Chris Kleponis | Getty Images

Melinda Gates, who runs the Bill & Melinda Gates Foundation with her husband, agrees.

"If you choose to have a partner in life, whoever you choose is probably the most important decision you make," she said during a conversation with her husband Bill and hundreds of high school students in New York City on Tuesday. It's "even more important than what career you have, where you go to college, where you go to high school."

That said, if you don't make the right choice initially, don't panic. "You can have a do-over. People do have a do-over with partners in life, but it's easier to have a do-over in your job and to change careers a lot than it is to change partners," she said. "So I say, try to pick very carefully and wisely."

Facebook COO and author Sheryl Sandberg, whose late husband, Dave Goldberg, was the CEO of SurveyMonkey, has a similar perspective. "I truly believe that the single most important career decision that a woman makes is whether she will have a life partner and who that partner is," she writes in her best-seller "Lean In."

"I don't know of one woman in a leadership position whose life partner is not fully — and I mean fully — supportive of her career."

If you choose to have a partner in life, whoever you choose is probably the most important decision you make.
Melinda Gates

These claims are backed by research. One study, by Brittany C. Solomon and Joshua J. Jackson of Washington University in St. Louis, shows that having a conscientious spouse can boost your salary significantly.

"With every one-standard-deviation increase in a spouse's conscientiousness, an individual is likely to earn approximately $4,000 more per year," the Harvard Business Review reports.

Additionally, "employees with extremely conscientious spouses (two standard deviations above the mean) are 50 percent more likely to get promoted than those with extremely unconscientious spouses (two standard deviations below the mean)."

Conscientious spouses tend to handle a lot of household tasks, which allows their partner to focus more on their career. And people tend to benefit from mirroring their conscientious spouses' diligent habits, the research team finds.

As Gates put it in NYC on Tuesday: "You will affect a partner greatly in life and they will affect you."

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