Why won't he leave?! Why does he keep coming back?!

I had a situation with this guy for about 4 years. We weren't dating or fwb or even fuck buddies, it was this weird phone/sexting/timed meet up thing that I couldn't even explain if I tried. So anyways over the course of four years we fought and I blocked him multiple times. Usually it was him coming back, sometimes it was me. This last time we had a massive fight and I told him I needed time away from him and i didn't know if or when I would contact him because I was just that done. This was back in April and this is the longest time he's ever been on block. I deleted his number and name but I also had it written down and hidden in my room before all this happened. He has no idea I still have his contact info. Three days ago I got an email from him pleading me to text him. I'm not ready to text him or even hear his stupid ass voice so I sent an email back asking wtf he wanted, let him know I deleted his shit, and that I'm not here for sex, sexting etc and that since day 1 all I wanted was a real thing with him. He hasn't responded, but I'm wondering why tf he keeps coming back?! He really can't tolerate it when I block him, he freaks out and contacts me or my friends every time. I don't know why he feels the need to do this.

I have no plans on starting up this ridiculous relationship with him again but I am curious to see what he says.