Kodomo no Omocha (TV), Kodomo no Jikan (TV) Recommendations
It's about an elementary school girl with a gigolo. Enough said.
Actually, the hired flesh in question, Rei, is more like Sana's bodyguard than what that term implies, even if she calls him her gigolo/boyfriend. Their relationship never goes further than an open crush she has on him. The show sometimes uses mature dialogues and themes, but apparently it's appropriate enough to show to (Japanese) kids.