I mean it's more like he forced himself to join the dirty side of the entertainment business for a long term connection or sth to support his career (could consider him as a victim of a power dynamic in workplace too) so that he can continue to be a star that MC would be so proud of, but he never did enjoy it. MC is the only one he feel safe (and also eager///) to touch and get touched, the guy disgusted everyone in this world but her. He actually tried to avoid getting touched by his co-actress in the party and also ask the director to cut off the kiss scene. I mean some ppl could consider it as physical cheating but I just personally saw that this psychopath doormat just want to do everything for MC with no care for any methods.
In the other hand, Chihiro cheated because of lust and selfish reasons.