“Take counsel with yourself, beloved, and ask whether you would indeed have me wait until I wither and fall from my high seat unmanned and witless. Nay, lady, I am the last of the Númenoreans and the latest King of the Elder Days; and to me has been given not only a span thrice that of Men of Middle-earth, but also the grace to go at my will, and give back the gift. Now, therefore, I will sleep.”

he explicitly chose to die before his time to prevent causing her the pain of becoming his carer