I've been thinking this since the beginning, but they should probably try to find that shaman that made that prediction in the first place. It's plain stupid that they're just blindly believing words from someone they've never even met.
Also, their siblings dated for 8 YEARS, but so far neither the FL or ML mentioned that their dating history was filled with accidents and dangerous occurrences. If marriage equals certain death, then dating for that long should've granted them at least a few injuries indicating what was to come, no?