Governor-elect Gavin Newsom's wife has gone through several titles as a political significant other: first, "first girlfriend," as she started dating the then-mayor of San Francisco. Now, Jennifer Siebel Newsom wants to be known as "first partner." Siebel Newsom, a documentary filmmaker, started dating Newsom, 51, in 2006, after his divorce from Kimberly Guilfoyle was final. The two married in 2008, while he was mayor. Newsom was elected lieutenant governor in 2010. The two have four children. Guilfoyle, 49, is now dating Donald Trump Jr., the son of President Trump.