Hi im trying to find a marriage between an owen rowlands born 1786 to catherine

the only one i can find is to a catherine williams, 27th sep 1827 but this would be 4 years after their first child was born? I have the family on census in 1841 in caernarfon. would love some help with it, trying to find catherines surname or any more info on owen such as parents. thanks in advance.