Judy,
You don’t say what denomination you think the family were. If Church of Ireland, the early records were destroyed in the 1922 fire in Dublin and they now have no baptisms earlier than 1879. They have marriages from 1845 and burials 1805 – 1831. Copies of the burials only are in PRONI (the public record office) in Belfast. The other records are held by the Minister, though the marriages from 1845 should be on the GRONI site for civil registration.
Ballycastle Presbyterian has baptisms and marriages from 1829. They are not on-line anywhere so far as I am aware, but there is a copy in PRONI.
Ramoan Presbyterian church baptisms pre 1900 were destroyed. Marriages from 1845 exist and are on the GRONI site.
All non RC marriages from 1st April 1845 onwards, in what is now Northern Ireland, are on the GRONI site. Marriage records pre 1845 are not on that site, and in many cases are not on-line anywhere either. So probably the daughter married before April 1845 and either that record is lost or is not on-line. You could try Ballycastle Presbyterian’s records but otherwise, I suspect the records are lost.