No this is unenforceable

Even a expertly drafted postnuptial agreement has difficulty stand up in court, let alone this amateurish "agreement". If you really care to draft one, consult your local lawyer. Postnuptial agreement's enforceability varies among 50 states. Check your state law

marriage.uslegal.com/postnuptial-agreements/


See this for how a postnup should include:

www.equalityinmarriage.org/dmpost.html