What's the title of this manga

There was a young boy who went often to his neighbor's house to read books or something. Then the neighbor started touching him and the boy felt nice. Then they were about to have sex then the boy got freaked out and ran to his parents. He didn't tell them anything though. Then when the boy had enough age he later contacted the neighbor again. The neighbor didn't like him at the first because he had grow up. But then they had sex and had a happily ever after or something

The neighbor was also a man and he was into childs