Susannah may be an illegitimate sister, not wife of Thomas, living with him in 1841 and 1851
In 1871, Susannah Greenhalgh (54, Wid, Cotton Reeler) was at Allsops Court, East Bolton with sons James and William (16 & 13). There is no common MMN for the sons so they may be illegitimate.
In 1881, Susannah Greenhalgh (60, Wid) was at 7 Shakespear's Court, East Bolton with son William (23).