Herald of Steel - Chapter 1393 Origins of Saffron

Before going to college, an ordinary high school student went to celebrate and got drunk. When he woke up, he found himself in a completely different world. There was a big sect, the approaching sect entrance examination, a slum where his body’s previous owner lived, and a shared memory about a missing young girl.

When he got tangled in a fight with a few punks in this different world, he fell off a cliff and miraculously found himself still alive, with two more voices ringing inside his head. They were Sword Master and Saber Master. In the company of them, he continued to find out more about this whole new world. He took the sect entrance examination, entered the sect, met a strange man in black, and even participated in a major competition of the sect to have a chance to win over his peers!
In this whole new world, he was born again and got to explore the fantastic martial world!

- Description from Novelupdates

In 2100 at the turn of the century the first full dive VMMORPG game 'Omega' was released

As childhood sweethearts, they were made to engage under the manipulations of their families. It involved having to to live in the same room and sleep together.

One night, she is accidentally made drunk, and in his delirium, he kisses her only to realize he enjoys it. From time to time, he would sneak a kiss on her, but his “crime” is eventually discovered in an accident. After being accused by her, he says with a smile, “You are my wife, why can’t I kiss you?”

The two people’s daily routine is full of bickering and mutual discrediting of each other.

Although he claims to disparage, he actually cares intensely about her. He feels crazily jealous when she is close to other men, to the point of tying her to his side, so that she becomes exclusively his.

- Description from web

The male student, Fukai Nagamasa, ignores his studies for college entrance exams in favor of following the path to chuunibyou. As he fainted during night cramming session before the exams, he realized that he was transported to a parallel world as a feudal lord in the Sengoku Era. Not to mention that suddenly, he was marrying the sixth Demon King, Oda Nobunaga’s little sister, the one who was purported to be an unrivaled beauty?