SO ANGRY 😡

ok so it's a long complicated story but to make it short, my bf asked me for a break because he was feeling depressed and wanted to seek help because he felt he couldn't give 100% to our relationship so i agreed to give him space and exactly a week later i saw him with his ex. This girl has ruined his life and i can't understand why he would chose her over me? He has been kicked out of his house because of her and i let him move in with me. She has cheated on him multiple times and verbally abused him. He has done nothing but lie and turned into someone i don't know. I have never felt SO ANGRY or this betrayed or hurt. How can i get over this??