Edward is thankful that Roy's house has more than one bedroom.
It's a lonely existence – he spends his days curled up in Roy's guest bedroom, curled up under a heap of blankets, listening to Roy's footsteps. Every now and then, the door opens. If Edward could find the strength, he knows he will look up to find Roy standing there – tired, dishevelled, worried. But he's weak. He can't bring himself to meet Roy's eyes anymore; not now that the man knows what he's done.
Really, he's just surprised that he's not out on the street yet.
Edward knows what he's done is the ultimate betrayal – especially now that Roy has let him back in, admitting in his own way that he loves Edward too. That should comfort him; there is finally someone who loves him despite his faults. Even though he's scarred and half metal and a sinner, he is loved. Roy is just as damaged as Edward, and he knows that if he clings, Roy will cling back. Neither of them will ever show it, but they need each other like a drowning man needs air. And Edward knows that this is it. There has been no other, and there never will be. And, as arrogant as it may sound, he knows that Roy, too, will have no other. He knows that there is no other that will see Roy's scars and burns and love them. There is no other who will look past what happened in Ishval and love him. There is no other who will see his haunted look on rainy days and just know. In a perfect world, time would be insignificant to them. In a perfect world, they would have something that could almost transcend time itself. It would be so pure, so raw and passionate that it would burn everything they touched. And they would revel in every minute of it.
But Edward has singlehandedly stopped them from having that. They will not have anything remotely close to that; it will be melancholy and desperate. Every touch, every glance, every word will be tainted with the knowledge that Edward's clock is ticking. Soon, he will just be another loss that keeps Roy up at night. He will be another person that neither of them could have saved.
He has destroyed Roy's last chance at happiness, as well as his own. Rather than having someone that will help him carry the weight of the world, he has deposited it on Roy's back and shackled them both. His poor choices will to haunt both of them; long after Edward is gone and forgotten. He knows that Roy will not forget.
Edward doesn't know where his soul will go after it's taken from him. From what he's read, he knows that he's going to suffer. And he will deserve it.
There's little consolation in that.