It would be helpful if you included the names of their parents. The marriage certificate does not. The problem is that there are so many "Jeremiah Fitzgerald's".
There is a baptism for a Jeremiah Fitzgerald in Aghada parish in1835 whose father is Bartholomew and another whose father is Patrick recorded in www.rootsireland.ie This appears to be an error? The online baptisms for Aghada are from 1838. It will be necessary for you to contact Mallow for clarification.