The Brotherhood of Trees — Michael Jasper

In an attempt to get in better shape, Matthew has taken to jogging in the woods behind his house with his two dogs. One morning he encounters a strange visitor to his woods: a boy, lost. He and his partner Fred never wanted kids, but Matthew forms a bond with the boy that he neglects to tell his partner about.

First published in Aeon SF, this is a story about aging, selflessness, and compassion.

Review:
“The protagonist and his partner are depicted with compassion and pathos, and not the over-the-top camp behavior many other authors use to depict gay characters. This, coupled with the neat backstory and polished prose, makes this a tale worth reading.” -- Tangent Online