Why would my ex partner cheat on me with his new girlfriend?

Anonymous
After we broke up in August last year, he got into a secret relationship without my knowledge. He told me, he was single In October last year. We hooked up once he lied to me saying his single than we got back together in late October than, I broke up with him for good, I got my belongings back from his, 13 weeks ago. I only just had found out the other week, he cheated on me with his new girlfriend from September last year than two other woman when we got back together, His also a kid toucher. I feel sorry for his new woman he keeps cheating on her I choose to stay away from it she was already warned by somebody, she just wouldn’t listen. I wish I never dated him. I hope I don’t ever have see him again. I blocked him on everything he got banned from social media for years anyway because his kidder toucher.
Why would my ex partner cheat on me with his new girlfriend?
5 Opinion