The Reverand and Mrs
This could be done in several ways. I believe the current best practice would be The Reverend and Mr. Smith.
Hello.
addressing attorney and wife
Dr. and Mr. Smith.
Rabbi and Mrs.
Pastor is entirely proper, so is reverend. Since they usually have Doctor of Divinity degrees, Doctor is often a preferred title, especially in the more evangelical churches.
Dr. and Mr. Smith
Dear Mrs Ambassador..
vmrs
"Dr and Mrs Smith" is the correct salutation. (With Smith replaced with the correct surname)
probabaly just a mrs. would suffise