When my husband walked away from our marriage without working on it I was devastated. You can read many of the stories here. Yes it was a blow to the ego, but even more because it made me question not only his characters but his failure at committing to his vows.
If husband was to return, In order for it to work, he would need to be willing to humble himself, take ownership that leaving the marriage was a mistake, take ownership of his flaws. He would have to be the one to show me that he truly wants it to work and will be putting the work into it. Not passively waiting for me to fix something he discarded. If he could not do this, I know our marriage can not ever work because he doesn't want it badly enough to.
And marriage is tough. In order for it to work, both people need to want it to.