My FMIL is wonderful, but very religious. She is a devout Catholic, and both her previous sons had Catholic priests officiate the weddings (even the son who is Episcopalian.)
My fiance doesn't care who officiates, as he is agnostic and never goes to church, other than when the family insists on it (holidays, christenings etc.)
I'm agnostic, but was raised Episcopalian, and have a few priests who did a lot for me when I was young. I'd love to know my officiant, and have it be someone who positively effected my life.
If I knew a Catholic priest, or my fiance knew one, who we were connected to, perhaps I'd consider having a Catholic priest- but we don't. I don't feel comfortable with a stranger up there bringing in religious aspects neither I or my fiance ascribe to.
FMIL asked if we'd have a Catholic priest- I told her probably not, and explained my close connection with the priests from my private school days. She seemed unhappy with this- and seems to think only Catholic priests are 'real' priests- but didn't press the matter.
I respect her beliefs (as much as I can), but I'm not compromising on this. Neither her son or I are religious, and he has no connection to any Catholic priests.
Any advice from those of you who have gone through this? I don't want this to turn into a 'thing.' I love his mother dearly, and want things to continue as smoothly as they have.