This particular John Leming, according to Sam K. Leming's book, was married first (1740) to Mary Coxe , then second (1787) to Louise Grogan. In the will of Thomas Salter (died 1790) of Philadelphia he mentions his "sister" Mary Leaming. Her husband is not mentioned (perhaps because he was dead?). Many have ASSUMED that Mary Leaming (sister of Thomas Salter) is identical with the Mary Coxe (daughter of John Coxe, cordwainer) who married John Liming in 1740. This may be true, but there are a few problems:
Mary Leaming was still alive in 1790 (per Thomas Salter's codicil to his will). This is in conflict with John Leming's marriage to Louise Grogan in 1787. So unless John Leming and Mary Cox divorced sometime between 1785 and 1790, there were apparently two DIFFERENT Mary Leaming's.
The Mary Leaming (sister of Thomas Salter), in my opinion, was probably NOT the Mary Cox who married John Liming in 1740. But I can't be certain without additional information.
It is also intersting that James Cravens of Chowan County, in his will, mentions a "Mary Leeming" and a "Peter Leeming." I don't know how they fit in the Leming genealogy.