Ex bf kept complaining about me now he is dating a copy of me and shoving it in my face. It really hurts. How should I react?

While I was dating my ex for 3 years I was modeling and finishing medical school. On IG I would share photos of me modeling and he would never like them or be supportive saying it was ridiculous that I need to focus on more important things and put me down. I broke up with him to see if he will change and see what life is like without me. Instead now he is dating another model doctor and always likes her photos of her modeling, shares photos of them which he would never do with me. Why is he acting differently with her. It kind of hurts