It seems that Nancy and Lucy have very different takes on the aftermath of Edward's disinheritance. Nancy:

"And after thinking it all over and over again, he said it seemed to him as if, now he had no fortune, and no nothing at all, it would be quite unkind to keep her on to the engagement, [snip] He could not bear to think of her doing no better, and so he begged, if she had the least mind for it, to put an end to the matter directly, [snip] And it was entirely for her sake, and upon her account, that he said a word about being off, and not upon his own."

And from Lucy's letter:

"he would not hear of our parting, though earnestly did I, as I thought my duty required, urge him to it for prudence sake, and would have parted for ever on the spot, would he consent to it; but he said it should never be, he did not regard his mothers anger, while he could have my affections"