Nesbitt was married to Sonia Forbes-Adam, the daughter of the Reverend Sir Timothy Forbes Adam. The two met when Nesbitt went to the final call-back for "Hamlet" at Loughborough Hall in 1989, and they soon began dating. They split up for a year after the release of "Hear My Song" but reunited and married in 1994. They had two daughters, Peggy and Mary, both of whom appeared in the final two "Hobbit" movies as the daughters of Bard the Bowman. In October 2013, Nesbitt announced that he and his wife would separate after 19 years. They were divorced in 2016.