Green’s Dictionary of Slang

joy of my life n.

one’s wife.

1936		(con. 1900s) F. Richards Old Soldier Sahib (1965) 41: A good deal of rhyming slang was used in those days [...] the wife was ‘joy-of-my-life.’.
1960		J. Franklyn Dict. of Rhy. Sl.
1972		Dodson & Saczek Dict. of Cockney Rhy. Sl.
1998		R. Puxley Fresh Rabbit.
2002		B. Kirkpatrick Wicked Cockney Rhy. Sl.