MGR HUSBAND'S PARENT'S FROM BOYE CO DERRY."
Hi ww1614, I went back to RootsIreland to be sure about the "MGR" reference and they re-affirmed my earlier answer.
In RootsIreland marriage records, or those records which appear on related websites such as AncestryIreland.com (the Ulster Historical Foundation website, there may be others), no matter what denomination of church the marriage relates to, the notation "MGR" (usually in a comment field) signifies that the words that follow are a comment added by the inputter of the data (for clarification). That is all that "MGR" means, it has no genealogical or religious significance (though the following comment normally will).
Another typical example is "MGR: Both fathers deceased"
Hope you find this useful.
Regards.