Melinda Gates described her marriage to Bill Gates as 'irretrievably broken' in a divorce petition which revealed she and the Microsoft founder, who is the fourth richest man in the world with a fortune of about $130billion, did not sign a prenuptial agreement. Bill, 64, and Melinda, 56, announced their split after 27 years of marriage via Twitter on Monday. Court documents obtained by DailyMail.com showed the couple do not ...