Sir I want to your suggestions after agreeing to this clause “will I be able to claim maintaince from her for my child in future”
You can ask your employed wife to undertake the expenses equally or at least to bear it some extent as she is also liable for the child's maintenance since she is well employed and drawing a handsome salary. You can file a maintenance case agaisnt her i through a court of law in this regard at any stage after the child is brought under your custody.
And if I claim can she claim any thing after divorce
Since she is employed, her claim may not be maintainable.
And if yes I can claim what arguments can I put in court to counter this clause
If there is an agreement between you both, the court will not interfere in it.
However you can state before court about the facts and can request the court to direct her to bear the responsibility equally.