William Sterling did have a (first) wife by the name of Elizabeth.
And Elizabeth Sawtell, by a process of elimination (of other daughters) must be "my daughter Sterling" in the 1692 will of Richard Sawtell.
IF Elizabeth (Sawtell) Sterling was alive at the time of her father's 1692 will, then she could NOT have been the first wife of William Sterling, as that wife died 6 Feb 1675 in Haverhill.
But was Elizabeth (Sawtell) Sterling alive in 1692? The will makes a bequest to "my daughter Sterling's children." Richard doesn't make a bequest to his daughter, but to is daughter's children, implying she was no longer alive.
"Richard Sawtell of Watertown" argues for her husband being Daniel Sterling who died in 1690 and was single in 1688. What's weak about this theory is lack of documented children to Daniel, and clearly there were at least two Sterling children per Richard Sawtell's will.
I'm actually leaning towards the William theory for lack of support for the Daniel theory.
Other opinions?