1. A tribunal of this State issuing a spousal-support order consistent with the law of this State has continuing and exclusive jurisdiction to modify the spousal-support order throughout the existence of the support obligation.
2. A tribunal of this State may not modify a spousal-support order issued by a tribunal of another state or a foreign country having continuing and exclusive jurisdiction over that order under the law of that state or foreign country.
3. A tribunal of this State that has continuing and exclusive jurisdiction over a spousal-support order may serve as:
(a) An initiating tribunal to request a tribunal of another state to enforce the spousal-support order issued in this State; or
(b) A responding tribunal to enforce or modify its own spousal-support order.