Story that takes place in nature and includes a threesome

[somethingj]

I read this story a year or two back and it involves a guy hiking to his favorite swimming hole in the woods and discovering there is a girl skinny dipping there. They then get it on and promise to meet up every year. And later on she brings another girl to double the fun. Any help would be appreciated.

 

[Apologies]

Pic or it didnt happen

Did the man also happen to a photographer and when he gets home his wife/ girlfriend finds the pictures?