OP, I think you should re~consider not making the commitments. While I totally see your point as I am a parent of teens as well, I am of the opinion that you should do everything you can for your child to succeed in something positive such as sports. Playing sports is keeping her away from bad habits such as gangs, drugs, etc. Also, this is only a temporary thing. One day she will be all grown up and on her own and you just may regret now doing this one thing for her.
However, if you truly are
dead set against making a commitment and nothing will change your mind, perhaps you can work out a compromise w/your daughter. There has to be some other person that your daughter gets along w/that you can trade driving duties w/. I would ask your daughter to be a little proactive and ask around and see.
As for your marriage issues, that is a tougher issue.
It sounds to me like you and your wife are just together for the family's sake
only and that you are simply roommates that are co parenting together.
And that is a very sad situation.