What's the name of this movie...?

I only remember bits and pieces. But I takes place in a farm type place in the 50's or 60's (I think). Some teenager becomes infatuated with either his friend's mother or his stepmother. I remember a scene where he spies on her bathing in a pond or something like that. No it's not a . It probably came out in the late 90's or early 00's.