I'm trying to write a few stories on the realistic side.....
One is about a man's ex_wife, he sees her years later after she's been bodybuilding for a long time. He night see her at a sex performance club where she is with another man on stage. Another version is he sees her at a baseball game with a much older man and he tries to determine their relationship.
Another is a divorced dad sees a muscle mom at his kids soccer practice.
Another is the same divorced dad goes to an open house at his sons school a nd meets the new lady strength and conditioning coach.
A few others...A father in law lusts for his muscled daughter in law. Or a man hangs out at his friends house and admires from afar the friends bodybuilding wife.
Another done before in some form...A guy with a martial arts fetish has his stash discovered by his wife. She trains to please him on their anniversary years later.
