Kore wa Koi no Hanashi
It's a 21 year age difference between novelist (32yrs) and a girl (11yrs). "I am sorry madam, I love her. I am in love with Haruka. We've already been together for 7 years now. She's the same as family to me. She's so important to me, that now I cannot consider letting her go anymore, so I don't want to let her feel sad and I don't want to lose her. I understand your feelings of not wanting to leave Haruka alone but please let her go. If you are afraid to die alone, I will accompany you. If it's just a matter of being unhappy or afraid to to alone, then as long as there's someone with you, it doesn't matter who it is right? The reason why you don't want to leave Haruka behind and want her with you is because she's also precious to you, right? Haruka isn't a child anymore either. You can talk to her about anything, no matter how painful or sad, you can speak openly. She'll understand."
Reimei No Arcana