Fib, at the end of the day, I know you want what is best for your son. I think what is best for him is that he feels loved by both of his parents. He needs to feel safe right now. He needs to feel that he could go to either of you and tell you his feelings. It is difficult for boys. Mine is 18 and does not ever tell him what he is feeling.

So, let me ask you, did either of you ask him if he prefers to ride in with his team? Perhaps that is a question you could ask.
Not to put any pressure on him to choose between you and his mom, just if he wants to ride in with his teammates.

Dont worry about the control thing. It doesnt matter right now.
Just get your kids through this with the least amount of collateral damage.

Do what will make him happy on this day. That is what is important. The other stuff between you and your w, and the issues you both have with each other, leave between the two of you.

Whether you are in control or she, emasculated or not, crazy or not, who was right or wrong, etc. leave it for another day, FIB.

For this day, for your son, do what you think is best for him. Make a happy memory for him amidst the turmoil. You will be glad you did.