There are a number of trees on ancestry that show Elizabeth Hayward as the wife of Henry Jefts b 1659.
I'd like to propose that this stems from the assumption that "Jr" means "son of the father with the same name", as it has come to mean,but it often simply is used to distinguish between two living related persons.
Henry born 1659 already had a son Henry b 1705 when Elizabeth Hayward's son Henry was born in 1717. Barring a will which shows Henry b 1659 had two sons named Henry, I think it much more likely that the father of Henry b 1717 and Elizabeth Hayward husband was Henry born 1688, the son of John Jefts b 1651, the brother of the "original" Henry Jr.
Note that in the Billerica Birth records, Henry "jr" is not called "jr" in his son's birth record in 1705 because his father had died 5 years earlier, no confusion as to which Henry.
Also there is no mention of a third marriage for Henry "Jr" in this book http://books.google.com/books?id=Pjv_DkWD83wC&pg=PA291&a...
I'd welcome any docs that support a contrary view.