The 12-year relationship of college sweethearts Mark Zuckerberg and Priscilla Chan

Facebook CEO Mark Zuckerberg $4 that he and his wife, Priscilla Chan, are expecting their first child together.

Zuckerberg and Chan are college sweathearts. They tied the knot on May 19, 2012, one day after Facebook's IPO.

The wedding was a surprise for all of the guests, who thought they were attending a medical school graduation party for Chan.

The couple met in line for the bathroom at a frat party 11 years ago. Now Chan has been dubbed the "first lady" of Facebook, and the pair have been extremely generous with their fortune.

Here's a summary of their time together, as told through their Facebook timelines.