Between 1973 and 1975, John Lennon and Yoko Ono separated for a period he later called his “Lost Weekend.” During this time, he dated his assistant, May Pang, and the pair moved to Los Angeles together. The two had a loving relationship, so Pang was upset when John Lennon referred to it as his “Lost Weekend.” According to Pang, the former Beatle did apologize for calling their relationship this.
Pang started working at Apple Corps., the company founded by The Beatles, at the age of 19, and she shortly became the assistant to Lennon and Ono. The couple started having marital problems in 1973, and Ono approached Pang asking her if she could start a relationship with Lennon. Pang repeatedly said no, but Ono was adamant about orchestrating everything.
Lennon and Pang did start dating, and they moved to LA together. Lennon was still having a rough time being away from Ono, and his drinking problem worsened, leading to several public drunken outbursts. However, “Lost Weekend” also saw a musical explosion from the former Beatle as he released three albums: Mind Games, Walls and Bridges, and Rock ‘n’ Roll. The “Lost Weekend” ended in early 1975 when Lennon abruptly reconciled with Ono.
Source: Ross Tanenbaum/cheatsheet.com