(a) "Property settlement or separation agreement" means a written agreement between a husband and wife whereby they agree to live separate and apart from each other. A separation agreement may also:
(1) Settle the property rights of the parties;
(2) Provide for child support;
(3) Provide for the allocation of custodial responsibility and the determination of decision-making responsibility for the children of the parties;
(4) Provide for the payment or waiver of spousal support by either party; or
(5) Otherwise settle and compromise issues arising from the marital rights and obligations of the parties.
(b) To the extent that an antenuptial agreement affects the property rights of the parties or the disposition of property after an annulment of the marriage or after a divorce or separation of the parties, the antenuptial agreement is a separation agreement.