should i go

so my mil and boyfriend announced they were getting married and that’s awesome but the date they planned for is when my husband and i are out of town so we cancelled the trip. THEN come to find out their not signing any papers legally saying their married bc 1. she wants the money from her dead husband (he was a firefighter) 2. their doing it bc he church thinks it wrong that they live together and are not married... we’re also not fond of the guy bc ge beat up my older BIL and pushed my younger BIL (which i don’t agree with at all)

my problem with this is they’ve been going to that church for 2 years so what’s the problem now.. so are we still obligated to go to this “wedding” or should we rebook our trip?

Edit: we were planning on going but she recently told us to sell our puppy all bc we asked her to puppy sit so this is why i don’t want to go anymore. We’ve also had to cut contact with her multiple times before as well.