Can't we all just get along?
I concur with others who suggested the OP work this through their SPG ambassador. Maybe there is a Starwood property that would work, or (I would hope) the ambassador could still work some magic even with a Marriott stay.
If it has to be a Marriott stay and the ambassador is no help, then others also have the right idea. Take the time to search for the property that seems to offer the best mix of benefits and cost, then reach out to them directly to politely inquire about possible special treatment. If it was me, I would highlight my wife's birthday and leave any mention of ambassadors, being new to Marriott, etc. out of it.