By law on party may be entitled to receive spousal support (aka alimony) from the other party if there is a difference in the parties' relative economic circumstances. Typically, if there are expectations or trigger events, like having children, caregiving to aging parents, injury, or career changes, couples can choose to modify or keep spousal support as the default state law.
Couples can agree to waive their right (either or both parties) to receive spousal support from the other party in the event of a divorce or separation; however, keep in mind, the court has the discretion to override a spousal support waiver if they find it would be "unconscionable" to enforce the waiver against a party, based on the circumstances present at the time of the divorce or separation.