I also found this petition interesting and wondered what became of Sarah's children. It would appear that she kept them.
Here is Sarah living with her children:

1850 Census Not Stated, York Co., VA
Sarah Gresham 39 F W b. New Kent City, VA
Elizabeth Stuart 18 F Mul b. James City, VA
Wm Stuart 1 M Mul b. York Co., VA

1860 Census James City, Williamsburg, VA
Sally Gresham 53 F W b. Hanover Co., VA
Mat Ashby 29 M Mul Shoemaker b. York Co., VA cannot read or write
Elizabeth Steward 27 F Mul b. James City Co., VA cannot read or write**
Wm. H. Steward 10 M Mul b. Williamsburg, VA
Amanda Simpson 13 F B b. James City Co., VA

** In 1850 she wasn't marked as illiterate. This may simply have been the assumption of the enumerator.

1870 Census Powhatan, James City, VA
William H. Steward 30 M Mul Labourer b.VA
Sarah J. Steward 28 F Mul Keeping House b. VA
John Steward 10 M Mul At Home b. VA
William H. Steward Jr. 7 M Mul At Home b. VA
Edward Steward 5 M Mul At Home b. VA
Mary J Steward 3 F Mul At Home b. VA
Elizabeth V. Steward 1 F Mul At Home b. VA

1880 Census Powhatan, James City Co., VA
Buck Steward B M 45 Head married Farmer b. VA Father VA Mother VA
Sarah Steward B F 41 Wife married Keeping House b. VA Father VA Mother VA
John Steward B M 20 Son single At Home Remarks: Burnt b. VA Father VA Mother VA
William Steward B M 17 Son single Farm Laborer b. VA Father VA Mother VA
Mary Steward B F 13 Dau single Farm Laborer b. VA Father VA Mother VA
Elizabeth Steward B F 10 single At Home b. VA Father VA Mother VA
Cornelia Steward B F 8 Dau single b. VA Father VA Mother VA
Nathaniel Steward B M 6 Son single b. VA Father VA Mother VA
Catherine Steward B F 4 Dau single b. VA Father VA Mother VA