I know it's hard to see now but Ann is 100% right about every word she typed. It may not make you feel less anger right now. You will get to a point where you finally say to yourself what I do when I think of my ex and a new woman........that basically I will pray for her because she will need it and the entire relationship will be based on lies.
You are better off without him. No one who would show up to your work flaunting a new relationship is worth having in your life. He will do it to her guaranteed. That's pretty low.