How long did john Lennon cheat on jis first wife with yoko?

John Lennon began his affair with Yoko Ono while still married to his first wife, Cynthia Lennon, around 1968. The relationship intensified during the recording of The Beatles' "White Album" and became public in 1969. Lennon and Cynthia's marriage officially ended in 1968 when they divorced, and he married Yoko Ono shortly thereafter in 1969. Thus, the duration of the affair overlapped with the final years of his marriage to Cynthia.