Air Force Instruction 36-2906, Personal Financial Responsibility requires servicemembers, in the absence of an agreement or court order, to "provide adequate financial support to family members." Para. 3.2.1.
Period. Unlike the other services, the Air Force does not attempt to define the level of support, instead leaving it up to the parties' agreement, and civilian courts if the parties do not agree. Even when a commander receives a complaint of nonsupport, the commander may require proof of support, but cannot define what constitutes an adequate level of support.
Support includes not only cash payments, but in-kind payments like buying groceries, paying bills, etc.
What does this mean? If you are a spouse separated from a servicemember, and need child support or maintenance, get a court order!