I would suggest that everytime you see him you think of how very blessed you are to have found out about his cheating personality NOW not after you've built a life together and maybe even be pregnant or have children, as happens to so many.
When you run into him, picture him having a hairy smelly butt and long ugly tail matched by his ugly penchant to hurt you. It may just make you smile.
As for you - take this as a gazelle that escaped being caught by a hyena today - and smile while you make plans for your WONDERFUL future without a person that would waste your energy....
You are lucky - even if it does not seem so right now.
You deserve someone that LOVES and appreciates you...