My ex left me in the same way. No explanations other than some vague reasons that didn't make sense. I think now that he felt guilty on some level for the stuff he was putting me through and eventually claimed that he needed a clean slate, to start a new life. Nice way to deal with guilt! Little does he know that the things we do follow us around, regardless of a new city or a new lover or a new job. And the cycle continues. I was the witness to his destructive behaviours and I figure that he thought that if he got rid of me, he would be absolved from the things he did. Could be similar. Stay tough!