it is a 50 year old Thai novel. It is better to understand the novel before watching the media adaptations.  One dialogue of the male lead was"You are only  my wife, not own my life."  So it just summarizes the male character's persistence to his shameless misbehavior and also one of the mistresses' shameless intruding.  The drama ends  with the male lead clenching his fist because either he hates the idea of a lifetime regret or, doubtfully, he realized a lifetime loss of something precious, which both were of his own doing.