Search Results: How did you find out you ve been cheated on

So my ex and I broke up in December, two weeks we got back together only for me to find out two days later he was cheating on me with someone he met the same night we got back together. Then he came back to me when that was over, then back to her. Then back to me. He chased one of his ex’s while he was with me, and has been after countless other girls. We’ve always remained in each other’s lives as my emotional support to him and we were sexual and have even discussed getting back together. On Thursday, we exchanged sexy text messages and he talked about wanting me back. Later that night, he went on a date with some tinder girl he’d met earlier in the week and as of last night they’re in a relationship. Yes, that fast. Ours was too. Except we lasted a year.
The thing is, my ex and I shouldn’t have lasted a year. He was emotionally abisive, called me names, made me feel worthless, often told me I was nothing to him and I never would be. He suffers from bipolar. Called his ex a whore for no reason. And now he’s with some other girl. And I don’t think it’s right that he started things when things were still going on with me. He blocked me on Friday; the day after our convo. And now part of me wants him to chase me, just so I can show him what he’s done to me. And the other part knows this poor girl should never experience what I have. Should I warn her? I have screenshots of every abusive message, every sext.