(a) The duties of support specified in §§ 501 through 504 of this title shall be performed according to the following order of priority:
(1) Duty to support one's own minor child;
(2) Duty to support a spouse;
(3) Duty to support a woman pregnant with child conceived out of wedlock;
(4) Duty to support a stepchild or the child of a person with whom the obligor cohabits in the relationship of husband and wife;
(5) Duty to support a poor person.
(b) Where a support obligor is unable to provide support adequate to the needs of 2 or more dependents of the same order of priority, a support obligor shall apportion the amount available for support as equally as possible between or among said dependents according to their respective needs.
(c) This section shall not repeal the rights of the parties as established by § 1512 of this title.