It is a very common pattern. Alcoholic husband, bitter and grandiose and full of resentment toward the world, makes his wife the target of all his bitter discontent and grandly walks out on her, telling her that she is the real problem in his life, and that it's time he got away from her controlling ways, and that he's going to "take a break" and "go improve himself and his life" because "this marriage is just not worth it."
What he really does is he finds more space to drink, more friends to drink with, and more excuses to keep drinking.
And then, right on the money, he shows up again. On the phone. In the email. At the door. "Let's talk," he says. And what he really wants is to be mothered, and because he hurt his wife so much, and she feels so terrible about herself, and because she is so grateful he is giving her a "second chance", she lets him back in.
Within days he's drunk on the couch. She is filled with rage and depression. He starts collecting all those resentments again. And things blow up. Again.
This can go on with some couples for a lifetime.
He left you because you are in the way of his reaching for the next drink.
If you get some counseling or go to a support group, you will clear up about what is really going on and you will not feel that sword in your heart anymore.
It is alcoholism.