So i was with my boyfriend for 3 years, and he broke up with me two weeks ago saying he wants to start a new life, all of a sudden. He said it without any emotions in his voice, and it was all of a sudden because before that everything was okay.

I was running after him, for the whole two weeks, and he came back, had sex with me, then left again after 3 days, again all of a sudden saying this;

Did he stop loving me? What's wrong with him? He blocked me out off his all social media and i feel so depressed. How can someone do this to someone they spent 3 years with, all of a sudden?