You can't take them back, no. But you can apologize and try to heal what you've done.

Holmes learned that well enough. God knows I didn't forgive him right away. But he tried. He did everything he could to prove to me that despite everything he'd done, despite the fact that he had a reason- that he knew it didn't excuse leaving me for three years. And he did everything to prove that he loved me despite it, and to prove that he deserved my forgiveness.

It's not too late to at least give him closure. Even if he never forgives you, he'll at least know there was a reason.