If you know your family lived in Northern Ireland you will need to search herehttps://geni.nidirect.gov.uk/
I was thinking more your Whittle/McCormack marriage as it doesn’t show up in marriages in Irish genealogy.
John McCormack married Christine Cullen in Cavan on 24 September 1879, they were both described as of the 'Theatrical Profession':https://civilrecords.irishgenealogy.ie/churchrecords/images/marriage_returns/marriages_1879/11075/8052659.pdf