According to USA regulations (tha ACCA and its implementation) basically every carrier at every airport is required to have an employee with authority trained in disability rules available at all times, typically by phone at outstations and at off hours. In the future ask for that person, called the CRO, IIRC for Customer Resolution Officer. This individual would have instantly known whether you were entitled to seats together and if so could have forced other passengers to be reseated to accommodate you and your spouse.
AFAIK you can also contact that person by phone after the flight to check on your rights in the situation and *complain* about your actual treatment when you traveled. Major airports might also have some all carrier disability access staff person who knows the rules.