A Cowboy's Love Affair

When Bob rented a horse to his old, now-married girlfriend, Jenny, he had no idea that she was interested in having an affair with him.  He realized this when she suggested that they go skinny dipping while they were out riding horses.  Before he knew what had happened, he was physically involved with her.  Her husband was a stock broker and didn't sleep with her very often. She was a good cook too, so his dad was happy to have her come around the ranch and sleep over sometimes.  Bob was happy to be having an affair with her but wished she would divorce her husband and marry him.
She was just waiting for an opportunity though, which eventually presented itself. This is an erotic romance.