Hi Reesoz
4330/1878 Charles L Slack married Isabella F A Stewart, in the district of ORANGE
3931/1873 William Henry Stanley married Mary Ann Jackson, in the district of HILL END
Please note that the brides surname is Jackson. It is the only one C1873. She may have married as a widow, or your Mary Ann may not have married in NSW.
You may like to have this moved to the Australia board.
Jamjar