Does anyone know where to get a marriage record if it does not come up under either name?

Alot depends on the when and the where of the marriage. In the US many states did not keep records until the early 1900s, was it before that time? Also not every marriage record is availabe thru search, maybe it has not been indexed yet, or Familysearch does not have access to the records at that location or during that time. I would go to the Familysearch wiki and do some research on the location where your people lived (so likely married) and see when marriage records started to become available. There will be links and ideas to help you in your search.