I just saw an absolutely brilliant musical about Elisabeth/Sisi! (It reminds me a bit of Nosferatu by the way)
The story begins with her assassin explaining that he killed Elisabeth because she wanted to die, having fallen in love with Death.
Essentially, when she was young, Elisabeth had an accident, but Death himself caught up with her, sparing her life because he falls in love with her.
However (after she falls in love with him in return at first sight), she begged him to take her with him because in his arms she felt safer than ever, free, and understood like with no one else. Death refused.
Time passed, and she ended up married, as we all know, to Franz and she no longer wanted to die.
However, Death returned, like a jealous lover, determined to take Elisabeth, who refused him.
He also telling her in passing that no matter how many dances she has, it is with him that she will have her last one (since he is death).
He would then stalk her throughout her life, trying to convince her to die whenever a problem arose in her life. And in the end, of course, they are united in death.
A must-see if you like relationships like Darklina, Saurondriel, Erikstine, Ellen & Orlok, Dracmina, Luc & Addie, Elizabeth & the Creature, Sarah & Jareth, etc.