I Parted Countlessly From My Beloved Over a Millennium, Now I Shall Become the Wicked Lady is a Manga/Manhwa/Manhua in english language, REINCARNATION series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.cc fastest updating comic site. The Summary is

From Gourmet Scans: "Swear... that you will never fall in love with me, no matter what." A thousand years ago, a sad fate separated this pair of lovers. No matter how many times they reincarnated and reconnected, it always ended with his tragic death... And once again they are reincarnated, as a count’s daughter, Amelia, and a marquis’s son, William. "I absolutely will not let him die this time!" Having decided this, Amelia swore that she 'won't love him anymore', and put on an act of being a wicked lady. However, puzzlingly, he is the one trying to get close to Amelia this time, and even sends her a marriage proposal...?!