[Gallagher]

Everyone in this situation will be biased. (A) for themselves, not wanting to lose someone they care so much about, but also wanting (B) to have as much happiness as they possibly can, because for dealing with all of that, they certainly deserve it. (B), from what I can gather, is likely to think that it's worth it to deal with some attitude, because there's so much more to (A) that more than makes up for it. Friends, of course, will likely side with those they're closer to, and in this situation, I think only (B)'s would be of any worry.

Everyone is likely to be against (B)'s wishes, but it's (B)'s choice to make. If they leave or if they stay, no one, not even (A), has a right to force.