Tell her that those expenses are hers to bear. You are already paying CS, and that, from my understanding, covers things like clothes, etc. So she wants D to get a friend a gift? Fine, she can pay for it. Don't pay for things that are outside of the MSA.
Childcare costs are another thing. There is no Her/Mine time. Children need care, and you are both to provide it. However, I would want receipts - it's tax-deductible. Plus at that point it should be nothing more than percentage of money you earn vs what she earns. Also, is this someplace where you can have the kids for an extra hour or two a week, by stepping in and taking that time? Would your work schedule allow that? I am all for trying to get more time with kids.
Depending upon your state, I would also look to file for reduced CS based upon a better income for her. If the state looks at both parents' incomes while determining CS, it will save you a bundle.
It also appears you don't have a right to know what is going on with the house until 12/31/2012 - a full year away. Frustrating, but if that is what is in the MSA...
Audaces fortuna iuvat.
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