My mother is an Asatru Shaman, my siblings are Asatru, I am a Pantheist and FI and her family are all Hindu. My mother has asked FI and I if we can perform a Asatru ritual at some point in the day (it's a ritual that only involves the wedding couple and immediate family, so it won't be during the ceremony) which FI and I have zero problems with, seeing as it is the religion I was brought up with and it's really important to my mother. We told FIs family about it and on the whole they were absolutely fine with it, until FI's mother found out that she had to be in the ritual. And now she says she's not coming to the wedding if she has to perform the ritual (which both FI and I think is bullshit), but all the same, we want her to be at least okay with having to do the ritual. I'm doing Hindu rituals that I don't believe in, but its really important to FI, so I'm quite happy to do them. My mother is paying for some of the wedding, I can't just turn around and say 'no, you can't have a ritual that's really important to you that we've already said is fine'. And we are just kind of lost with what to do.