Advice please

My boyfriend and I broke up almost 6 weeks ago. I was devastated but we agreed to be friends. We both agreed that we didn’t want to be out of each others lives entirely. At the time I figured I’d rather be friends with him than nothing at all. After the first week he thought we should have no contact for a while and I convinced him that we should he each other through it because we still cared about each other. We still talked daily. He still called me pet names like baby and hugged and kissed me when he saw me, there was even one day that we talked that he seemed to show signs of regretting leaving. I did made all the usual mistakes of trying to get him back, he never gave in to them, but they didn’t pay him away either. Having him as a friend made me feel better, probably because it gave me false hope. Then he started seeing someone else. We made plans to hang out one night and he cancelled on me. The next morning I drove by his house on my way to work (I know, another mistake) and there was a car there I didn’t recognize. In my defense, when he moved out, he moved two houses down from mine so it’s pretty hard to avoid his place. But anyway, as you may have expected, I didn’t react too well too him seeing someone new. It hurt that he was able to move on less than a month after we broke up. Everything I read is saying that it is probably a rebound, but it still doesn’t feel good. At that point I finally got my key back from him and started contacting him less. It’s been about two weeks since. I’ve tried the no contact with him, the problem his he’s contacted me a few times and I’ve had to start over. Once because he left some of his things and stopped by to get them and then there was yesterday… He heard there was a car accident near my work and messaged me to see if I was ok. I said I was and he told me he was worried. Then he stopped by later to pick up the rest of his things. We had a good casual conversation but after he left I couldn’t stop bawling. I know I’ve rambled on, but I guess my question is, had too much damage been done to try the five step system? And also, since I told him that I want to be his friend, how do I do no contact without being a bitch about it?