John Whitman, the husband of former Republican Gov. Christine Todd Whitman and the state's first-ever first gentleman, died Thursday. He was 71. He died at Morristown Medical Center after suffering a catastrophic brain injury in mid-June, said Heather Grizzle, a spokeswoman for Todd Whitman. John Whitman was an investment banker who served as a managing partner at Princeton-based Sycamore Ventures. He served as New Jersey's first gentleman from 1994 to 2001.