I am the secondary in a relationship with a married couple. We have been together for 2 years and she has the same issue. She has meltdowns,mood swings
And major jealousy. I have yet to get past it. We all live together and i have broken thing's off several times. I care enough to keep coming back but her issues are such a constant source of turmoil. I have been looking for advice and so far nothing helpful has come along
But i totally understand where your coming from.