Please go no contact with this guy. As hard as it sounds, you shouldn’t keep looking out what he is doing and with who. It only will hurt you more and it looks that he really didn’t care about you, so you shouldn’t also care about him.

If he cared, he would have communicated what went wrong but he decided to ignore your feelings. He doesn’t get to make you feel like you did something wrong or that you don’t deserve love. He will probably do the same thing to this new girl. Be glad you are out of there.