Would you ever contact an ex who cheated? Or have you ever heard from them again?

Just wanting some opinions. I was dating this girl for a while and everything seemed to be going great. We were even planning on getting married this year. Then out of nowhere I discovered that she was still married. Which she told me that her divorced was finalized and he was completely out of the picture. The messed up part is not only did she go back to him, but she was with him for a month before I even found out. While she was still making plans on getting married. It's been two months since I found out and I haven't heard a word from her since. Not even an apology. I know what she did was wrong and I would never take her back and she doesn't deserve to hear from me. But I can't help but still care about her and wonder how she is doing. Something tells me she might be a sociopath... Have you ever heard from an ex that cheated on you? Would you ever contact a cheated ex?