I did have this discussion too, only it ended slightly differently....
On occasion of my first marriage to a welsh Presbyterian, I did ask for the local catholic priest to bless the wedding and the rings, nothing else....
He came out with the same answer... He wanted A solemn promise to bring up any children in the Catholic faith....
I respectfully said that I could not promise anything of the sort as I wanted the kids to have their own choices as to what and who to worship. And that his request was bordering to blackmail... if not outright blackmail....
The priest got quite uppity and started quoting from some book or the other...
So I did tell him to shove it, as his blessings were no longer required...
Not in so many words, though....