Heartbroken and alone

This came out of the blue has has shattered my heart and world. My boyfriend calls me mid day and tells me he wants to separate and for me to collect my things little by little from our place yesterday. I was so shocked and still am. I cried myself to sleep wirh what little sleep I did get. I had to tell my boss and she let me take the rest of the day off to get things in order. I am at a loss for words. This came out of nowhere and I just dont know what to think. He and I are both plus size people. Just needing some reassurance that he will see the error. He had two kids that I have become a step mom to and this is going to shatter their world too. Their mom is an addict and not in the picture. I just dont know what to do.