Mary Furlong

There are very few Catholic records available for the 1700s in Ireland (assuming this Furlong/Whitty couple were RC) - without knowing where your Mary Furlong was born it would be very difficult to narrow the search and either confirm or rule out any potential matches.

Have you located details of the marriage ? do you know where in county Wexford it took place i.e. which parish ?

Marriages usually took place in the bride's parish so that would be the place to start any search, and see if the parish has baptism records going back far enough for your Mary...