Hitou Meguri The Animation 秘湯めぐり

Ken is an abandoned child, he was saved and taken by the master of an inn, there he meet Chitose, the next mistress of the Inn. Ten years later have passed now, Ken works at the inn helping out Chii-chan, he in reality has feelings for her, but she being the mistress...its like a wall is separating them. One day he witnesses Chitose having sex with a customer...after that we continually see her and hear her having sex with that man...what is going on? What will Ken do? is she willingly having sex with him?