Toaru Kagaku no Railgun SS - Volume 1, Chapter 5

With a marriage contract forcefully done, he married her, and all she could do was comply, and resent him deeply for that and for all the following misunderstandings they faced.
However, it was already too late when she understood she actually loved him.

He once stained the rivers and mountains with blood, his brilliance unparalleled. Unexpectedly, he encountered a great calamity, a dragon trapped in shallow waters, everyone thought he was nothing more than a useless son-in-law. But how could Gold Scales belong to a mere pond? The returning king, under the name of Frenzied Son-in-Law, with the War God’s stature, swept across the Eight Desolations of the Four Realms, the world trembled beneath his feet!

A protagonist reborn in another world.

[Mc takes consent from Woman not their husband][Mc doesn't want to NTR every guy. He only makes their wife cheat for sex.][Making friend's mom fall......is one of his big dreams.]“I like married women and there are so many noble women out there...”A horny Otaku from Earth gets transmigrated as an old Viscount.His lifespan is depleting too quickly due to an injury.Fortunately, there is a Ying Yang technique which can increase his lifespan.“This man has been single for his whole life and never touched a woman? WTF!!” Otaku is shocked from the Viscount's dry life.“I do have the maids, right?”[MC likes married women][Netori, Cheating, Blackmail]