Kerry the Vengeful PT

You and Kerry were good friends in middle school, but halfway through high school, she told you her secret: that she was a futanari. You betrayed her trust, telling a couple of your friends, who told their friends, and before long, the whole school knew, and she got bullied and had to transfer schools. Not before telling you how much she hated you of course. Now, over ten years later, you joined a new gym, and she's the resident personal trainer. Unless you pay a bunch of money to void your contract, looks like you'll be stuck with her for at least a year.