Sex kara Hajimaru Ai wa Aru no ka

After the divorce of her parents, Ari does not have it easy. Especially not when her father wants to marry another woman only a year later. Ari must absolutely prevent the wedding, and so she forges a plan: To show her father what kind of person his future step-son, Ritsu, is, she asks him bluntly if he wants to sleep with her. And indeed that night will change everything... (Source: AniList)