Marryat married Lucy Dorothea Clinton in St George's, Hanover Square, London on 9 July 1872.
About this period [1879] I took counsel of a friend, whose acquaintance I had made some short time previously, and who, in addition to being one of the best, if not the best dry-fly fisherman in England, was an adept in all the minutiee of dyeing, selecting, and preparing the materials, as well as the construction of artificial flies.
To this friend, George Selwyn Marryat, I desire to express the deepest gratitude for the unwearying patience and perfect unselfishness with which he gradually inducted me into every detail known to him, and gave me the benefit of his invaluable experience, concealing nothing which would tend to perfect me in the art of imitating the various winged inhabitants of the stream.Marryat wrote virtually nothing about the development the dry fly fishing at the time.
In his second book, Dry Fly Fishing: theory and practice (1889), Halford acknowledged his debt to Marryat's innovation and tutelage in the dedication.
Confined to his bed in his house at The Close, Salisbury, Marryat suffered a paralysing stroke that left him unconscious.
Shortly after Marryat's death, Major W. G. Turle, a close personal friend and noted angler (see Turle knot), wrote in the Fishing Gazette: For twenty or more years Marryat and his Tam O' Shanter were a regular institution on the Test, and great was the sorrow expressed by rich and poor when it was heard we should see him amongst us no more.