Neukdae Gongjagui Bimil
In order to hide his "secret", Alto only has dry sex after marrying Viviana. Viviana, who suffers a lot mentally and only gains experience with masturbation, decides to never marry Alto again in this life. Unaware of her regression, Alto promises to make an effort to have a satisfactory sexual relationship with her, thinking that he must stop her from acting emotionally...
(Source: Ridibooks, translated)