The Stepmother 11: Don't Tell Your Dad (2014)

Here's a sweet family story for you. The ambitious stepmom, sleeps with her husband's business partner, just not with her husband. The preppy son, who is obsessed with his stepmom, sleeps with his cheerleader girlfriend. Everyone gets laid except Dad. He's fantasizing about the cheerleader. Mom really loves her stepson. They wouldn't - would they????