I'd love to hear your thoughts!

Recently, an old acquaintance of mine from a past talking stage has ended up in jail. We had stopped talking about 4 or 5 months ago, but we managed to stay friends. A few months back, he mentioned that he had a girlfriend, which led us to talk less frequently. I was perfectly okay with this since I had entered a relationship as well. However, I received a call from him recently (from jail), and he informed me that he and his girlfriend had broken up. Apparently, the breakup happened because she saw messages from him expressing his love for me from months earlier, and he seemed to blame me for their split. At the end of our conversation, he mentioned that he would likely be calling frequently just to chat, and this is where my dilemma arises. I have no desire to engage in constant communication with him—or any communication at all, really—especially since I've moved on. I’m also concerned that he will overstep boundaries, as that’s his tendency. Is it wrong for me to block his number and decide not to speak with him again?