COMDINST M1000.6A, Personnel Manual, Chapter 8M (this is a huge 17MB document, which takes forever to load) sets out obligations of Coast Guard servicemembers to support their spouses in the absence of an agreement or court order.  Paragraph 8.M.3.c.

• Spouse only:  BAH-Diff, plus 20% of base pay.
• Spouse & 1 child:  BAH-Diff, plus 25% of base pay.
• Spouse & 2 or more children:  BAH-Diff, plus 30% of base pay.
• 1 child: 1/6 of base pay.
• 2 children: 1/4 of base pay.
• 3 or more children: 1/3 of base pay.

Child included handicapped children.

BAH-Diff is the difference between BAH at the With-Dependents Rate, and BAH at the Without-Dependents Rate.

Relief from Obligation

• For a child, when the child's whereabouts & welfare cannot be ascertained
• For a child, the person requesting support does not have custody of the child
• The spouse deserted the member without cause,
• The spouse committed infidelity, or
• The spouse inflicted physical abuse on the member.

The grounds for relief for spousal support are discretionary, and the commandant may not grant relief even if they are satisfied.  Furthermore, relief from spousal support does not relieve the member of the obligation to support the children per the schedule above.