Venerable Demon King & The Doting Immortal (QT) - Chapter 646: NSFW

At 18, Alex Kain is whisked away to Eryndor, a game-like realm where he gains 'Skill Synthesis', a talent to fuse skills into godlike powers. Battling monsters and conquering dungeons, he builds a harem of strong women drawn to his might and charm. With the power to return to Earth bearing incredible resources, Alex faces a growing threat that endangers both worlds in this epic of adventure, romance, and ambition.

Discovering that his wife was cheating on him with his superior, Jonathan Hayes was put on the combat list by his superior, a list that had already been concluded weeks ago.Wanting to survive from the war and come back to get his revenge on his wife and his superior, Jonathan was killed in the battlefield.Instead of going to heaven like every good man should, Jonathan woke up five years back in time, before his country was captured by the enemy, due to the help of his country's corrupt leaders. Jonathan knew his job immediately he realized what had happened to him. To liberate his country from getting captured again, and to get his revenge on his cheating wife and his superior.He had guessed correctly, but there was more to it. He not only went back in time, he woke up in a parallel world where magic was present. His job was not only to rescue his country from getting captured again, his job was to become the first warlord of the world. The first king of the whole world.[Congratulations, you have been rewarded with two unique skills from God]

This novel is also known as Master Fu's Mysterious Darling Wife

She is the The Young Miss of Military family Shen, her face is peerless, her temperament is cold, and she is her family’s treasure, but isn’t accepted as one’s child by her mother;

He is The Sole Heir to the top giant Fu Family, his power is unparalleled, indifferent high-born, the captain of the mysterious military force, and the youngest commander-in-chief.

Because of her grandmother’s wishes, she married him at lightning speed. She thought that it was a marriage that she needed, but she didn’t expect to be greeted with his extreme pampering.

- Description from Novelupdates