hmm I think we need another person's opinion, BUT from what i understand...
electronegativity refers to the "pull" that the electronegative atom has on the other atom that it is bond to. So, for example the nucleus of O has a strong "pull" on the electrons of it's 2 H's in H20.
..whereas, electron affinity of an atom refers to the ease by which that atom can ACCEPT another electron.
So.. i think the diff lies in that fact that electronegativity is about keeping what u got, while elecron affinity is about acquiring what you don't have.
..hope that makes sense 🙂