My partner left me for his cheating manipulative ex

Stephanie

So my now ex walked past his ex when he was out with friends and felt like he missed her, he then sat and had a conversation with me about our relationship and ended the conversation if I see her I couldn't help myself around her.

A few days before when we were laying in bed he had explained she cheated on him, manipulated and controlled as well as cheated on him while he was at a low point in his life. He then left me for her, we had a great relationship, both in and out the bedroom.

I'm now doubting everything we had, and myself.

Is it bad that I miss him and wish that he hadn't left?