But by the Grace of Dog (Four-Legged Friends #1)
A.F. Henley

However, Thom's new fur buddy has no such need to keep to itself and immediately befriends the man Thom has secretly coveted since he moved in -- Justin, Thom's gorgeous, bright-eyed neighbour. No matter how Thom tries to evade the man, the dog keeps drawing them back into each other's lives, and it doesn't take Thom long to recognize it's simply pursuing the demands of Thom's own heart. With the dog giving him the courage to try, Thom reaches out to return the love being offered.
Until a stranger shows up insisting the dog is his and demanding its immediate return ... a loss Thom knows will take all of his efforts and newfound confidence with it.