Perhaps that wasn't your Mack in 1880? Could Sallie and Rose be the same person?

Source: Marriages, 1831-1950 ; index 1831-1972 Madison County (Florida). County Judge
Batch # M513382 Years:1868-1876 Source Call #0959775 IT 2 Type: Film

MACK WILLIAMS
Marriages:
Spouse: ROSE MATTHEWS Family
Marriage: 14 APR 1871 , Madison, Florida

Messages:
Extracted marriage record for locality listed in the record. The source records are usually arranged chronologically by the marriage date.

Could this be Rose Matthews?

1870 Census Madison, Madison Co., FL
Benj. Mathis 65 M B Works On Farm b. SC
Sallie Mathis 50 F B Keepings House b. SC
Susan Mathis 18 F B Works on Farm b. FL
Rose Mathis 15 F B Works on Farm b. FL
Richard Mathis 13 M B b. SC