Bill and Melinda Gates have had a decades-long agreement that the Microsoft boss could vacation for a long weekend at the beach every year with his venture capitalist ex-girlfriend.
The odd arrangement raises eyebrows now that one of the richest couples in the world are going their separate ways after 27 years together and building a $130billion fortune.
Bill, 65, and venture capitalist Ann Winblad, 70, dated in the 80s but broke up in 1987, the same year he met future wife Melinda. Ann was reportedly more ready for marriage than Bill as he worked day and night to build his billion-dollar Microsoft empire.
However, the pair maintained a friendship and in a 1997 piece in TIME Magazine, Bill said, 'When I was off on my own thinking about marrying Melinda, I called Ann and asked for her approval.'
She approved and the former lovers - with Melinda's blessing - kept their yearly vacation alive, with Bill spending a long weekend with Ann at her beach house on the Outer Banks of North Carolina.
The pair spend their getaway every spring riding dune buggies, hang-gliding and taking walks on the beach.
'We can play putt-putt while discussing biotechnology,' Bill said in the 1997 interview.
Ann said, 'We share our thoughts about the world and ourselves. And we marvel about how, as two young overachievers, we began a great adventure on the fringes of a little-known industry and it landed us at the center of an amazing universe.'
Bill and Ann first met in 1984 at a Ben Rosen-Esther Dyson computer conference.
While in different cities, they began going on 'virtual dates' by going to see the same movie at the same time and talking about it on their cell phones. She even convinced him to stop eating meat for a short time.
They broke up three years later, but in the TIME Magazine piece, Ann was quoted telling Bill that Melinda 'would be a good match for him because she had intellectual stamina.'
The pair even got into business together and in 1999 Bill partnered with Ann on Hummer Winblad Venture Partners.
Ann is married to San Francisco private investigator Edward Alex Kline, 63. Kline is the younger brother of actor Kevin Kline.
Bill and Melinda both posted the same joint statement about their divorce on Twitter Monday, which read: 'After a great deal of thought and a lot of work, we have made the decision to end our marriage.
'Over the last 27 years, we have raised three incredible children and built a foundation that works all over the world to enable all people to lead healthy, productive lives.
'We continue to share a belief in that mission and will continue to work together at the foundation, but we no longer believe we can grow together as a couple in this next phase of our lives. We ask for space and privacy for our family as we begin to navigate this new life.'
In papers filed in Washington state, Melinda, 56, described their relationship as 'irretrievably broken'
The couple's eldest daughter, 25-year-old Jennifer Gates, has spoken publicly on social media about the 'challenging stretch' the family recently endured. Neither of their two other adult children have commented.
Jennifer is the oldest of Bill and Melinda's three children, followed by 21-year-old son Rory and 18-year-old daughter Phoebe.
No other details of why the pair are splitting have been given but the court papers reveal the pair did not have a prenuptial agreement in place when they married in 1994 - putting their $130billion fortune at the center of the split.
In the divorce petition, which was filed in Superior Court of Washington - King County on Monday, Melinda asked the judge to dissolved the marriage 'on the date stated in our separation contract'. The separation contract was not included in the filing so that date is unclear.
Melinda says in the petition that spousal support is 'not needed' - meaning she won't seek regular payments from Bill but take a settlement which is likely to be privately negotiated, if it hasn't already been decided upon.
Lawyers are shocked there was no prenup, given Bill had already made his first billion dollars at the age of 31 in 1987 - the same year he met Melinda. Now, their myriad assets are up for grabs.
While the couple have no prenup, it appears a lot of the work of dividing up their estate - which includes properties in five states, a private jet, an astonishing art collection and a fleet of luxury cars - has already been done, as their divorce papers repeatedly refer to a 'separation contract' which both have signed. The contract itself has not been made public.
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