Can you describe the power imbalance? Within the company, in principle he has authority, but for one thing, he can't act with impunity. He's responsible to the Board and shareholders, so if he promoted, demoted, fired, or otherwise exercised that authority unfairly, he could be held accountable, so that power is limited.

For another thing, his authority is only one source of power. She can go to the media, where even allegations could inflict huge damage. In this case, the employee seems to hold tremendous power since she could publicize a consensual (with her), though extramarital (not likely, though possibly, consenting from his wife) relationship in the workplace.

I'm not saying good, bad, right, or wrong. I'm just wondering what the power imbalance is in practice.