No agreement of such type has any legal enforceability in India.
In other words the legal right of oa maintenance and custody of the child for a parent can an not be relinquished by way of any agreement.
Marriage survives on mutual trust and faith and if you make so much of permutation and combination even before you take your wife with you then even if such agreement was valid then also this marriage would not have worked.
This is a not job or service where you would plan the actions of your employee before hand.
She is your better half and hence either trust you like a spouse or get away f this marriage amicably.