Presumably, the OP has left. Just the same, I desire that their situation move to some form of peace.
The advice and observation from @GalaGirl is still ringing in my ears and is, possibly, the most fundamental direction toward solution for many troubled situations:
GG said "Relationships need to be healthy. It could be healthy friendship, healthy family, healthy coworkers, healthy monogamy, healthy polyamory, healthy kink, etc. But the main point is HEALTHY, regardless of relationship type."
