Reincarnated as My Husband's Mistress

As a grand duchess with a body like glass, I lost my life in a severe seizure. No, rather, I thought I had lost it. "...I want you." Then, I was reincarnated as a woman who looked just like me. However, isn't this woman's body too healthy? The joy of having a healthy body is brief, everyone says this to me. Because this woman is my perfect husband's mistress. I attended my own funeral in order to hear the truth. I saw a handsome man there, crying even more than my own husband, as if the world had suddenly collapsed. Who is that man, whom I've never seen before? And actually, this woman... Is she my husband's mistress? (Source: Naver Corporation, translated)