A threesome

unbelievable betrayed.

unsafe because it's such a sociopathic move on both their parts that I would feel like neither my marriage nor my family of origin were safe for me.

I'm so sorry this is happening to you. It's highly abusive.

Please get some support from an individual therapist. IMO, there is no way to maintain a marriage on these terms and you will need to create a lot of distance with the perpetrator brother and navigate some sticky family of origin issues.

Uh angry.

Betrayed.

And heartbroken.

Double whammy.