The uke moves out of his parents home and starts living by himself, he meets this guy that he sleeps with and that he really likes, I think maybe his neighbor, that ends up being an investigator or secret detective that his parents hired. To see whether the uke was sleeping around, I think, when the uke finds out he tells the investigator that he slept with him because he loved him not because of money. Please help me find this manga I dont know if it's a manga with multiple stories or not, but I've searched and searched and cant find it!

Try the second story from Mr. Convenience by Yamato Nase.