Are you referring to marriages that occurred after 1854, which would appear on the Fauquier Co Marriage Register? If so, email me directly at the address below with more information about the people you seek. I also have numerous references for Loudoun as well as a few for Clarke County.
The only mention of a Dunaway on the 1854-1882 Fauquier Marriage Register is as an official.
Note that is is always beneficial to have some dates in any query, so there is no question as to the time period you are interested in.