The Strongest Son-In-Law In History

Having traversed to another world and become the pampered son-in-law of a wealthy family, he was expelled for being too incompetent. Consequently, he worked hard to improve himself and sought to marry a more powerful, stunningly beautiful, and noble heiress, becoming her husband.

Practicing martial arts is impossible, it will never be possible in this lifetime; one can only rely on living off others to sustain oneself

I want to train my wife to become the world's number one expert. Anyone who dares to provoke me will be dealt with by my wife!