alt Hacker NewsThe term already has a well-established meaning; we shouldn't change our understanding of it. If you mean something else then use different terminology.
Also, I don't think there was an "extreme power imbalance". If anything, she had far more power over him than the other way around, since he had much more to lose and she could blackmail him with making the affair public or other allegations.
I am referring to the meaning established in the law. Many things fall under the legal umbrella of sexual harassment. If you want to describe it as something else maybe you should be the one looking for a new term to coin.