Am I losing my mind?

I broke up with my boyfriend over the summer. After five months of spending practically everyday together (we both attend the same university) I broke up with him because I was tired of his immaturity. We decided to stay friends since we both really missed each other. We both agreed that we were better as friends and enjoyed it way more than our relationship. Because of this, we established some ground rules for our friendship such as no flirty comments and compliments, no physical touching outside of a friendly hug, and that each of us should date other people if the opportunity presented itself. However, we were both physically attracted still so we had a few fwb moments (just making out, not sex which we never actually engaged in). These moments always led to him confessing how he felt about me (he felt like he was still in love with me, and I wasn’t too sure I wasn’t in love with him still either). Sure enough, he met a girl and asked her out. They never actually had an official date but at the time, he thought they might date at some point. Meanwhile, I met a guy during a summer internship and we immediately hit it off. The night everything came to a close, me and said ex-bf were FaceTiming and we got on the topic of our relationship. One thing led to another and I wound up mentioning that I was hanging out with the guy I met at work (we had talked previously about him so it wasn’t a surprise). I hadn’t planned on it because I was trying to keep my love life out of the picture. Our FaceTiming session and friendship ended once he decided that we shouldn’t be friends anymore and that he didn’t care that much anyway. He didn’t give me a valid reason, although I know it’s because he still cared about me. I haven’t spoken to him since that time (7/5). The man I’m dating now is amazing and I can’t imagine what I did to deserve everything that he is. What’s been bothering me lately though is how I left things with my ex. I’m paranoid all the time that I’m going to run into him on campus or see him somewhere. I have a few of his things and I think that just handing them to him and walking away would make me feel so much better. Just so that I would have seen him since our final split. Does that make me crazy? I have no feelings for him at all whatsoever anymore. I would just love to hand him is stuff with the typical, “I don’t want this anymore”, and walking away. Am I insane??