Bill and Melinda Gates, who have been married for 27 years, have announced that they’ll be separating.

The Microsoft co-founder revealed the split on Twitter Monday afternoon, sharing that the longtime couple have “put a great deal of thought and a lot of work on our relationship.”

“Over the last 27 years, we have raised three incredible children and build a foundation that works all over the world to enable all people to lead healthy, productive lives,” he wrote. “We continue to share a belief in that mission and will continue our 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.

The now-former couple has run the nonprofit Bill & Melinda Gates Foundation for over 20 years, as co-chairs and trustees. It is reported to be the largest private foundation in the world, with $46.8 billion in assets, according to a website fact sheet. Bill also owns 1.37 percent of Microsoft’s outstanding shares, which FactSet reports are valued at $26 billion.

The pair got married in Hawaii in 1994 after they met at Microsoft, where Melinda was a marketing manager. The news of their split comes two years after Jeff Bezos—another of the world’s richest figures—announced a divorce from his wife MacKenzie.

Bill and Melinda both created the Giving Pledge alongside Warren Buffett to give away half their wealth.