Struggling to move on from relationship

I am struggling to move on from a relationship that ended over a year ago. I thought the world of him, we had future plans and big conversations. But he was deceitful and unfaithful and shortly after I found out I had an STI. I was left utterly devastated. He completely cut off all contact and refused to address it with me. While the STI was easily treated, my emotional distress has not eased and I find myself teary and getting upset at what he has done. He has moved on very quickly with multiple partners and life is all fine and rosy for him. I feel like I’ve been left to pick up the pieces. I feel so ashamed and have not discussed this with friends or family. They all thought he was wonderful. I don’t want to feel like this anymore but my trust was completely eroded and I don’t know how to ever give this to another person. I feel sad and violated.