I don’t know what to do

So on November 4, my ex sent me a message on Facebook messenger. It was just “hi.” I technically didn’t open it, but I could see a preview of it. I had just ended things with a guy I was seeing and I just didn’t have the energy to deal with my ex. At that point we hadn’t talked since September 20, so he was unaware I was seeing anyone. Hell he’s unaware I’ve even found a job. So today at about an hour ago, he texts me. It just says “hi.” Again I don’t reply back. Than I guess since I didn’t answer his text, he calls me. At the moment I wasn’t near my phone so I didn’t pick up. He never leaves a voicemail. I don’t know how to talk to him. There was a while I stopped talking to him (from October of last year to August of this year). He had met someone but was still telling me he needed me and craved me. I just thought it was best to stop talking to him. During that time he would continue to message me on a regular basis even if I never replied, even calling me baby at one point. When we started talking again, I let him know how bad he hurt me. We started to get along, but he would still cross the line (FYI, he still had the same girlfriend and as far as I know they’re still together). Our conversation in September wasn’t a bad one, I just didn’t text or call him since because I chose to concentrate on the guy I was seeing. Now I feel like if I start talking to him again, he’ll cross the line again acting like he wants only me. Part of me knows I should completely walk away from him, it’s just he doesn’t make it easy. And I don’t want to fall into his trap because I’m trying to get over who I was seeing. I guess all I can do for now is to just keep ignoring his messages and calls.