Why did he leave?

We were so happy and then we started drifting off but we still texted but he didn’t text as much as we used too. And one day it was an emergency and I needed to call him and I told him and he said that “Tristan *his bsf* was here can’t talk gtg” I was crying so I stopped texting him to see if he would text me and I couldn’t hold back do the third day I texted him and I said “heyyyy” he replied in “hi” I was like I miss you and he said “ ik but I don’t” I put a “?” He said “like I don’t miss you “ and I said “oh” he said “yea I have 10 b words in my snap and I’m blocking you”. And to this day I still text him even though he blocked me.