'O No My Love not I' is a widely printed broadside ballad c1780-1860. It varies quite a lot. An 11st version The Forsaking Maid's Resolution appears in The Hunter's Garland BL 11621 c 5 11.2 but other versions range from 5 sts. I think 'The Newfoundland Sailor' which has sts in common is a later offshoot. Off the top of my head Mary's version is pretty standard with a chorus made of bits of commonplaces.