回复：敲打敲打你。

If I assign 2 people one project, I may have 2 reasons:

1. The first person is not capable so I need 2nd person to overlook or review his work. The 2nd person is usually more experienced than the first one otherwise it is not helping.
2. It is too much workload on one person especially this project has a tight deadline.

If it is due to 2nd reason, I honestly don't care who did more and who did less or who is better, as long as the project is successfully completed. Regarding to who is more capable on certain area, unless you are brand new or this project is super super visible and it is a new project, you manager should already know about it.
Different people have different strength or weakness. In manager or director's perception, they may think you guys are perfectly matched or essential for the success of this project. Once the perception is there, it is hard to change unless there is a big problem or a big success.
My advice is: pick up your fight and don't fight on small things. I also agree that you shouldn’t give him too much information.