This is familiar territory to me. I was in a similar position some 15 years ago. I am Lutheran. Wife is Catholic. Our original plan was to be be married in the Catholic Church, but this “promise” really ended that. When I asked her priest why he would think, even though it’s not required of me, that I would ever do anything less than all in my power to raise our children Lutheran he had no answer.
To me it was as if I was being asked to admit and accept that my religious beliefs were lesser and there was no way I was ever going to do that. If the promise had been to share, explore, examine, learn I would have been fine with it.
For my wife, who already rejected many Catholic teachings, the decision to be married in a Lutheran Church was not difficult. She remains a Catholic, but the experience was such a bad one that she has never even looked at convalidating (I’ve suggested it a number of times) our marriage taking the attitude that only her, I, and God know if our marriage is valid and everyone, and everything else with an opinion on it, makes no difference. I truly have no idea why she is Catholic at times.