Red was familiar with pain. He was familiar with someone loving him and leaving him. He knew what it was like to get properly intimate with someone, to know them like he knew himself. The resets made sure of that.
He just didn't expect you to leave him so suddenly.
He didn't expect this to hurt as much as it did. If he had to compare this with something, he would say that it was on par with dying. And he definitely knew what dying felt like.
He poured a significant amount of the whiskey he was drinking onto your grave.
"A toast, doll, for our anniversary." he said, "May you and our little one be at peace."
It never got any easier with each passing year.