He married Letitia Whyte (1801–1844), daughter of Captain Charles Whyte of Loughbrickland, Co. Down, Ireland in 1817. They set off on a year-long tour of the continent in 1819. The marriage was not a success and in 1825 the couple split up with an acrimonious public controversy with Letitia requesting a legal separation on the grounds that "the union proved to be of the most unhappy nature: the treatment which Lady De la Beche received at the hands of her husband being such as to render it impossible for her to live with him." De la Beche obtaining a legal separation and custody of their two daughters in 1826. Letitia moved in with her lover, Major-General Henry Wyndham, son of the earl of Egremont.