Hiyori-chan's manga / #Brother-in-law(1)

Well, what did i just read... 5 chapters of confusion... First he dates the brother, is jealous of the sister, then marries the sister but keeps doing shit with the brother, divorces the sister after a year, goes back to the brother, ruins the relationship between brother and sister, brother doesn't seem to give a fuck tho.... what? Like, what just happened in this manhua? Like i feel if it had more chapters and was worked out better story wise, it would definitly be interesting!