Well, that might be possible in a rather variant text, but in Laurence Price's original of Feb. 1657, it is James Harris (the demon lover) that says he has been away seven years. Although previously engaged to him, she (now Jane Renalds) had waited three years for him, but had then had married a carpenter and had three children.

Seven years is sort of the standard amount of time for a lover to be absent in the 'broken token' ballads (faithful lovers).