The decades-long relationship ofBilland Melinda Gates started out over a shared passion for puzzles, problem solving, and math — yet it seems the puzzle of how to save their 27-year marriage is one neither can solve.

The couple married in 1994 seven years after first meeting. On Monday night they announced that they woulddivorceafter more than two decades of marriage. In a joint statement posted on Twitter, they revealed they no longer believe they can grow together... in the next phase of their lives.

In their public statements, both Bill Gates and Melinda Gates noted that they had done "a lot of work in our relationship" — during which time they welcomed three children together, founded a charitable foundation, and amassed a joint fortune of $130 billion, largely through his technology company Microsoft.

It was that company that brought the two together in the first place, after Melinda was hired as a product manager in 1987. She was also the only woman selected from the company's first batch of MBA graduates.

The couple's romance began after they sat next to each other at a business dinner in New York City. According to Melinda, they "got to talk at dinner that night" and she could "sense he was interested," and a few days later when they bumped into each other in the company parking lot, he asked her out — even though his initial proposal wasn't "up to her standards."

"He started a conversation and asked me out for two weeks starting Friday," she revealed in her 2019 book, Moments of Uplift: How Empowering Women Changes the World.

"I laughed and said, 'That's not natural enough for me. Ask me out closer to the date and give him my number.'"

Undeterred by her initial rejection, Bill called Melinda two hours later and asked her to go out with him that evening, jokingly asking if such a brief date would be "spontaneous enough for her."

Melinda recalls how the couple bonded over their shared love of puzzles and their competitive natures: “We found we had a lot in common. We both loved puzzles and we both loved to compete. So we had puzzle competitions and played math games. I think he was intrigued when I beat him at a math game and won the first time we played Clue, the board game where you figure out who killed someone in which room with what weapon. He urged me to read The Great Gatsby, his favorite novel, and I read it twice.

"Maybe that's when he knew he had met his match. He would say his romantic match. When we got engaged, someone asked Bill, 'How does Melinda make you feel?' and he said, 'It's amazing, she makes me want to get married.'"

However, Bill's offer was not a decision he took lightly - quite the opposite, in fact.

In a 2019 Netflix documentary about the Microsoft founder, Inside Bill's Brain, the couple revealed that they weren't entirely serious about their romance in the first few months; Melinda actually dated a few other people in the early days of their relationship, while the "other woman" in Bill's life was his beloved computer company.

"She had other boyfriends, and I had Microsoft," Bill said. "We were like, 'Hey, we're not really serious about each other, are we? We're not going to demand each other's time.'"

Melinda agreed: "I was new to Microsoft, there were a lot of men there and... I was still looking around."

Billionaire Bill Gates family.

Both admitted that they were somewhat surprised when they realized that they were in love, however it was in the moment they confessed those feelings to each other that they knew they had to make a decision whether their relationship would lead to marriage or should end.

For Bill, the issue wasn't whether he wanted to be with Melinda, but rather whether he was truly capable of being a husband while still focusing on building his tech empire.

“He wanted to get married, but he didn’t know if he could really commit and still run Microsoft,” Melinda explains in the Netflix documentary. “He had to make a decision…”

Recalling the problem-solving skills that first interested Melinda, Bill decides to pursue the most logical solution to that question—by completing a pros and cons list, laying out all the negative and positive aspects of a potential marriage on a whiteboard in Bill's bedroom, which Melinda actually catches Bill filling out.

While neither of them revealed the exact specifics of Bill's list, it seems the pros outweighed the cons, and they got engaged shortly after — although they didn't actually get married until a few years later, in a beautiful ceremony held in Lanai, Hawaii.

Even during the wedding ceremony, Bill's logical side continued, with Melinda recalling on Instagram while marking their 25th anniversary how he "did some amazingly quick math to figure out" how they should cut the cake so all their guests would have a piece of the same size cake.

Less than two years after their wedding, Melinda found out she was pregnant with their first child — daughter Jennifer, now 25 — and she found herself facing the same question her husband had answered with his list of pros and cons: could she, and would she want to, balance her career at Microsoft with her role as a mother?

At the time, Melinda said Microsoft was such a big part of the couple's life together — so much so that she actually considered not telling her husband about the pregnancy until days after she found out, because they were about to take a rare vacation, and Melinda wanted Bill to be able to relax.

"In 1995, after Bill and I had been married for almost two years and were about to go on a trip to China, I found out I was pregnant," she writes in her book. "This trip to China was a big deal for us. Bill rarely took time off from Microsoft, and we were traveling with other couples. I didn't want to mess up the trip, so I considered not telling Bill I was pregnant until we got back. For a day and a half, I thought, I'll just keep it quiet. Then I realized, 'No, I have to tell him because what if something happens? And basically, I have to tell him because it's his baby, too.' And then, when I sat Bill down to talk about the baby one morning before work, he had two reactions. He was very emotional about the baby, and then he said, 'Are you going to pretend you didn't tell me? Are you kidding?'"

Melinda also shocked her husband when she announced that she would not be working again after having children - a decision she said left Bill horrified.

“He was stunned,” she recalled, revealing that he simply replied, “What do you mean, you’re not coming back?”

"And I said, 'We're lucky enough that we don't need my income. So this is about how we want to build a family. The hours I need to do a good job and raise a family at the same time.'"

Over the next decade, the couple welcomed two more children; their son Rory, now 21, followed by their second daughter Phoebe, now 18.

Although Melinda did not return to work at Microsoft, the couple grew together professionally again in 2000, when they founded their nonprofit, the Bill & Melinda Gates Foundation, which is now said to be the largest private foundation in the world.

The foundation's focus is improving health care, promoting education, and addressing global poverty. When the nonprofit was founded, Bill stepped down as CEO of Microsoft and moved into the role of director, relinquishing control of day-to-day operations so he could focus more of his energy on the couple's philanthropy.

But while the relationship may seem idyllic on the surface – courtesy of the couple's spacious homes, lavish vacations and numerous public charitable endeavours – behind the scenes, Melinda admits that they have had to work incredibly hard to make their marriage work and ensure that their lavish wealth does not negatively impact their children.

Immediately after Jennifer's birth, Melinda said she felt "very alone" because her husband spent so much time at work, leaving her to take on the majority of parenting duties, and she admitted she questioned whether he really wasn't taking fatherhood seriously.

“When we first had Jenn, I felt very alone in my marriage,” she explains in her book. “Bill was CEO of Microsoft at the time. He was so busy; everyone wanted him, and I was like, ‘Okay, maybe in theory he wants kids, but in reality he doesn’t.

Over the years, however, the couple have worked together to create “equal” roles — and turned their marriage into a “partnership,” which has seen them both take on childcare duties, including Bill offering to drive their daughter Jennifer to school a few days a week, because it meant spending more than two hours in the car each day. Bill has also taken on the dishwashing duties for his wife, whenever they have the chance to eat together at home.

In a 2019 interview with The Sunday Times, the mother-of-three confessed that there were days in her marriage when she questioned whether the couple could keep going - however she said they worked at it and eventually got to a place where they "can laugh about almost anything".

Both Bill and Melinda went to great lengths to ensure that their children would have as normal an upbringing as possible, given the family's incredible wealth - and all three enrolled in school under their mother's maiden name so as not to draw attention to their background.

The Microsoft founder revealed in 2017 that he banned his children from using smartphones until they were 14, a decision that left his three children very upset.

“We don’t have mobile phones at the table at meals, we didn’t give our kids mobile phones until they were 14 and they complained that other kids were getting mobile phones earlier,” he explains.

Bill has also said repeatedly that he will not give his children large portions of his fortune as inheritances, instead capping them at $10 million each — a relatively small portion of his $130 billion fortune. The majority of the couple's money will go to charity; both are part of The Giving Pledge, a group of some of the world's wealthiest people who have vowed to give at least half of their wealth to charity.

But their children's upbringing was anything but modest; the family owns multiple properties across the United States, including their one-of-a-kind headquarters in Washington, a $125 million compound called Xanadu 2.0.