Manga wo Yomeru Ore ga Sekai Saikyou ~Yometachi to Sugosu Ki mama na Seikatsu~ - Chapter 86 – Demon King Immediately Falling Within Two Panels

An old man dies, torn by regret. Due to his high karma, he has “near-limitless possibilities for reincarnation”. He chooses to reincarnate in a fantasy world as a voluptuous futanari succubus with big tits and an irresistible smile.

He is a legendary business powerhouse, a King with a business empire. She is just an ordinary female student. A deal, – a paper marriage, a marriage for four years. Four years later, she turned away fearlessly. She thought that their path would never cross again, but he took her in his stride and refused to let go of everything about her, even interfering with her getting close to other men!

This novel is also known as Long Live the Mad Wife!

Daughter of the Feng Family, born a waste. Forced to marry a fool in an attempt to expel evil influences. When the first killer from the 21st century possessed this body, the sky and the earth surged. She was indifferent and cold-hearted but she let her guard down around him alone. She thought he was a pleasant sheep but didn’t expect him to be a gray wolf in disguise!

- Description from Novelupdates

Xin Yun, a sarcastic young man, traveled to an unknown world by chance, but lost his chance to become the strongest because of his obsession with women... or sex. In a collision of the powers of nine powerful men, an incredible thing happened. Xin Yun was reborn back to the time when he traveled to the Isekai world. A fantasy journey is about to begin... [The comic adapted from this novel is popular all over the world]