An Engagement Ring

Kuki Noriko is married to Kuki Michio, who is bedridden with illness. Though she loves her husband, Noriko is unhappy with the loss of intimacy in their lives. She discovers she is attracted to Ema Takeshi, her husband's doctor and that he feels the same way about her. Dr. Ema is lonely, and Noriko falls increasingly in love with the handsome, athletic doctor. The possibility of an affair arises, but Michio begins to suspect their relationship. Love, passion, and duty become more and more entangled until Michio rises from his sickbed and does something to force the issue.
(Source: IMDb)