Stick It

Haley Graham (Missy Peregrym) is a rebellious 17-year-old who has a run-in with the law when she and two friends go biking through a residential construction site. Haley is arrested and is forced by a judge to return to the regimented world of competitive gymnastics. Haley was once considered one of the most talented gymnasts in the US. One year earlier, she made it to the World Championships, but she walked out of competition in the middle of the finals, costing the American team the gold medal and leaving many people hurt and crushed, making her one of the most hated people in gymnastics.
Haley goes to the elite Vickerman Gymnastics Academy (VGA), her ultimate nightmare, run by legendary coach Burt Vickerman (Jeff Bridges). Haley has a talk with Coach Vickerman, who convinces her to take up the sport once againÂ â at least until she can enter an upcoming invitational competition. Vickerman convinces her that she can use the prize money from the competition to repay some property damage debts she still owes and leave gymnastics once and for all. Disliking the sport's rigid rules and intense training schedule, Haley is reluctant to come out of retirement. Her attitude toward her fellow gymnastsÂ â as well as her pastÂ â causes conflicts. After getting the cold shoulder the first day at the gym, Haley realizes what she is up against.
At the invitational, Haley's talent shines and her return from gymnastics retirement seems for the better. But all is not what it seems in the scoring system. She starts to remember one of the many reasons she retiredÂ â the flaws in judging. The panels do not look at the difficulty of the move nor do they look at the technique; they merely take deductions for unimportant minor errors. As Haley Graham says, "It doesn't matter how well you do. It's how well you follow their rules."
In addition, Haley is severely stressed by her dominating mother, who has arrived to watch the meet. Her conduct at the World Championship ("Worlds") has not been forgotten by the other athletes, and they treat her with open hostility. Haley finally breaks down in the middle of her balance beam routine and, in a repeat of the World Championships, leaves the arena before completing the competition. Before she leaves, she reveals to Vickerman the reason she walked out of Worlds: she had just discovered that her mother was having an affair with her then-coach, and her parents got divorced as a result.
Haley then goes back to the judge who sentenced her to the gymnastics academy to inform him that she has dropped out and wants to be sent to either a juvenile hall or military academy. But the judge tells Haley that Vickerman had just paid off all of her debit of the property damages in her incident with the law, and she is no longer under any legal issues. Haley then approaches Vickerman who confirms it by claiming that he used the money that her father had paid him for her gymnastics training. Vickerman persuades Haley to remain with the academy a while longer so she can continue with her training to reach Nationals.
Although she did not complete the invitational, Haley continues to train and, with three of her teammates Mina (Maddy Curley), Wei Wei (Nikki SooHoo) and Joanne (Vanessa Lengies), qualifies for the National Championships. The biased judging leaves her far back in the all-around standings, but this does not keep her out of the event finals. In the first event final, vault, Mina executes an extremely difficult maneuver perfectly but receives a low score (9.500 out of 10). When Vickerman questions the judges, he learns that Mina was penalized on the technicality of showing a bra strap. Haley is next up. However, instead of vaulting, she shows her bra strap to the judges and forfeits her turn in disgust (otherwise known as a "scratch"). One by one, the other gymnasts follow suit, earning a string of zeroes and forcing the judges to award Mina the vault gold medal anyway.
Haley's bold action sparks a movement. The gymnasts talk among themselves and realize that if they could choose the winner, the judging would be fair. They convince all the others in the competition to do the same, choosing one person from each event who they deem the best to be the "winner". The winner completes her routine; the others jump on and off the apparatus and scratch. It seems the movement will be ruined when Tricia Skilken, a long-time judges' favorite, arrives and threatens the choice of winners by competing herself. Trisha finally comes to her senses, though, and realizes that scratching is for the good of the competition to make a point.
What started out as a gymnastics competition turns into a small revolution for the rules and Haley. Her talents are recognized once more and her future seems to be set with numerous colleges offering her athletic scholarships to compete in NCAA gymnastics.

Question: With whom was Haley's mother having an affair?
Answer: Haley's coach