Co-written and first recorded by Carole Bayer Sager (1977).
Also recorded by Peter Allen, co-writer (1979).
Hit version by Rita Coolidge (US #38/MOR #3/C&W #32/CAN AC #1 1979).
From the wiki: “I’d Rather Leave While I’m In Love” is a song co-written by Peter Allen (‘Don’t Cry Out Loud‘) and Carol Bayer-Sager, and popularized in 1979 by Rita Coolidge, was first recorded in 1977 by Bayer Sager. Co-writer Allen recorded his own version of ‘I’d Rather Leave While I’m In Love’ in 1979 for his album I Could Have Been a Sailor.
“The song about breaking up was sung originally by its two songwriters, who both had married and later split up with famous spouses: Allen, from Liza Minnelli; Bayer Sager, from producer Andrew Sager.