No. The law does not describe a consensual relationship with a subordinate as "sexual harassment".

Obviously the situation isn't that simple, and neither is the law. If you really want to have a relationship with a subordinate there are legitimate ways to make that happen. He chose to circumvent those (ostensibly repeatedly, and while paying off people who found out about it), and the set of reasonable explanations that don't involve some form of harassment is vanishingly small.