Mark Cuban & Tiffany Stewart, Together For 18 Years

They randomly met each other at the gym in 1997. By that time, Mark Cuban had already taken some successful steps as a businessman, selling his startup, MicroSolutions, for $6 million. It was only after they started dating, however, that his career really skyrocketed.

Today Mark is worth the staggering amount of $4.2 billion. He and Tiffany tied the knot in 2002, two years after he had purchased the Dallas Mavericks NBA team. They’ve gotten to live in quite an opulent way, with Mark owning houses like a 24,000-square-foot mansion outside Dallas.