This comes from what I believe is Spike Milligan's only novel, Puckoon:
An Irish lady seeks counseling from her priest re: her troubles with her
husband. His response:
"Well, just because you don't like him is no cause for divorce. Now I'm
going to ask you a few questions. Has he ever beaten you?"
"No - I'd kill him if he did!"
"Has he ever been late with the money?"
"No, every Friday on the nail."
"Now, I want to you to think carefully on this one. Has he ever been
unfaithful to you?"
"By gor, I think we've got him there! I know for sure he wasn't the
father o' me last child!"