Standing firm when my kid wants to quit his team mid-season

My 12 year old joined soccer because his buddies did but now he says it's boring and wants to quit. I told him flat out that's not how we do things in this family. You commit to something you see it through. He's mad at me but he needs to learn that being a man means keeping your word even when you don't feel like it. Sometimes being the good dad means being the unpopular dad.