Kimi ga Ita Keshiki

I've been preparing for a competition that could open doors for me as an aspiring artist, but one day, in one fell swoop, I lost my art model and my girlfriend. I was still reeling from it when a young girl suddenly showed up beside me and said she would be my new model. However, now she says I need to offer up my body in exchange for her help...?! I had lost everything, and she knew nothing of the world; this is the story of our warped and fleeting, yet innocent, love. (Source: MangaPlaza)