My broski’s girlfriend is not my friend and never will be. She’s “cool” as long as she with him and doing right by him. If she’s not… she’s as good as an OPP.
The monster you saw at the end of the relationship is exactly who they are, don't make excuses for them. You can't have a healthy relationship with people who are wearing a mask. The red flags are usually there, you just have to keep your eyes open wider than your heart.