An afterthought: Lila and Enzo in Elena Ferrante's Neopolitan novels might be my best non-self-serving answer for now. I love the way they are present in each other's lives from childhood on, and the patient character of Enzo who is so unlike most of the male characters in these books. At least for a time, they become true collaborators. When their relationship does, finally, begin to crack under the strain of (deleted in order not to be a spoiler), I mourn for them.
Another afterthought: Mma. Ramotswe and Mr. J. L. B. Matekoni in Alexander McCall Smith's series (The Ladies Number 1 Detective Agency, etc.) are delightful, as are the books in general. I love their thoughtfulness, their caring not just for each other but for all the people in their world, and the fact that they can count on that about each other.
Another afterthought: Mma. Ramotswe and Mr. J. L. B. Matekoni in Alexander McCall Smith's series (The Ladies Number 1 Detective Agency, etc.) are delightful, as are the books in general. I love their thoughtfulness, their caring not just for each other but for all the people in their world, and the fact that they can count on that about each other.