David Goldberg, the well-known tech exec who died Friday while on vacation in Mexico, collapsed at the gym while exercising. Efforts to revive Goldberg, who is married to Facebook COO Sheryl Sandberg, were unsuccessful.

Goldberg's sudden death at age 47 led to unsubstantiated rumors that the CEO of SurveyMonkey and the husband of Facebook COO Sheryl Sandberg may have taken his own life. It is still not known why the cause of death was not released. Fortune magazine is quoting sources saying Goldberg’s family is still trying to piece together what happened.

“Dave Goldberg was on vacation with family and friends in Mexico,” an anonymous source told the magazine in an article published Monday. “He collapsed while exercising in the gym. Efforts to revive him at the gym and at a local hospital were unsuccessful.”

Goldberg’s brother, Robert, first announced the news in a Facebook post Saturday. The family is preparing a private ceremony and funeral in California, according to the New York Times.

Sandberg has not spoken publicly since Goldberg’s death, though she frequently cited their relationship as the reason for her own success. In her book, “Lean In: Women, Work and the Will to Lead,” Sandberg described how Goldberg prioritized her schedule and their two children over his own hectic, successful life.

“Even though Dave and I are extraordinarily fortunate and can afford exceptional child care, there are still difficult and painful decisions about how much time our jobs require us to be away from our family and who will pick up the slack,” she wrote, adding later that the couple decided at the beginning of each week who would focus on child care and housework. “We are never at 50-50 at any given moment -- perfect equality is hard to define or sustain -- but we allow the pendulum to swing back and forth between us.”

Goldberg founded the music company LAUNCH Media before selling it to Yahoo in 2001. Goldberg worked at Yahoo until 2007, when he joined Benchmark Capital before taking the reins as CEO of the data company SurveyMonkey in 2009.

The power of his partnership with Sandberg was on display when, in a “60 Minutes” interview, Goldberg revealed that he pushed Sandberg to ask for a higher salary when she accepted a job from Facebook CEO Mark Zuckerberg.  

“Not because the money mattered so much, but it was because of the principle,” Goldberg said. “I wanted Mark to really feel that he stretched to get Sheryl, because she’s worth it.”    

Goldberg is survived by Sandberg and the couple’s two children.