If you think Butler is a possibility, I recommend you contact the Genealogy department of the Butler Public Library. The head of that department, Lu, has been incredibly helpful to my mom and me in our efforts to research mom's family. In addition, you may find the marriage record in the Butler County Courthouse -- I'm not positive of the date range when marriages were recorded, but we found both a marriage record (1897) and divorce decree (1912) for my great-grandparents the in courthouse records.
One more suggestion -- many of the Butler church record are now available on Ancestry. We found records from both the Lutheran and the Methodist churches online. Not sure whether the Catholic church records are digitized.