Some of the pay to view sites might have the marriage records. otherwise there should be a copy in the National Library in Dublin, and PRONI in Belfast also have them. This is what PRONI has:
R.C. Knockbride (Kilmore diocese) Baptisms, 1835-79; marriages, 1835-79; deaths, 1835-76 MIC1D/82.
Unfortunately the PRONI and National Library copies are not on-line and a personal visit is normally required to access them. (You can ask PRONI if they will do a look up but there will almost certainly be a fee).