I have a fair amount of info on the Tillett's but the Mary Tillett you are asking about is also a dead-end for me.
I descend from two of Thomas (d. bet. Jul 1796 - 2 Feb 1797)Tillet's daughters, Hannah and Sarah. We know who his sons married so she was not the wife of any of them.
The 1754 list of Men Belonging to Capt. Jacob Farrows Company - includes: Rw. Tillett; John Tillet; Thos. Tillet; Isaac Tillet. MY guess is they are all brothers?
So Mary could have been married to one a son of one of these men. I just have not actively pursued these other Tillett men.