Complex sentence: Wapner has expressed holding great resentment and bitterness at the court show's producers for finding out this way, and additional resentment over being let go when, according to him, the show was doing well.
Split into simpler sentences: Wapner has expressed holding great resentment and bitterness with finding out this way. In addition, he holds resentment over being let go when, according to him, the show was doing well.