This mellow funk version of the Sly & the Family Stone hit was issued shortly after Sly's single topped the charts in 1971.
According to YouTube poster fonsoul, whose channel boasts an eye-popping collection of 1,500 soul, R&B and blues selections, The Family was a group of Philadelphia studio musicians that included Leon Huff on keyboards, Ronnie Baker on bass, Earl Young on bass, Roland Chambers on bass and Larry Washington on congas. This was the group that evolved into MFSB after a name change in 1973 to avoid confusion with a British rock band.
Producers Huff and Kenny Gamble put this single out on their North Star label. It was reissued in 1973 under the MFSB name on Philadelphia-International, which the producers had formed in '71. By this time MFSB had become the studio band that backed nearly all of the label's hit records as well as waxing their own instrumental recordings, including the 1974 No. 1 hit TSOP (The Sound of Philadelphia).
An extended version of Family Affair (4:21 as opposed to the single's 2:17) was included MFSB's self-titled 1973 album, which is available as a download and on a recently issued British CD.
The flip side of the original Family Affair single contained something called Nation Time, and here it is from fonsoul's collection.