There are two bmd websites for Belfast, Antrim.www.emeraldancestors.come
both a pay websites but emerald allows you to view first but I think the second would be easier to use both their names to look for a marriage. I would put the year
about 1830. You can also then search for any other
siblings if there were any.
You can also look in the Tithe Applotments but early for James as they probably didn't have their own place till after marriage. 1820-1839www.genealogy.nationalarchives.ie
if still in Ireland for the Griffith Valuation 1846-1864 try:www.askaboutireland.ie