Because of his affair with Abigail Williams, what does John Proctor fear
doing?

Answer:
Its d cause if he tells she's lying he is exposing her
Explanation:
Expose her on trials. John Proctor fears exposing Abigail Williams on court since he has no fehacient enough proof that could demonstrate that she is, in fact, a liar. There's the affair issue going around as well, he fears that this could come out at any part of the trial and of course, he wouldn't be trusted or worse, he could turn into a suspect.