He has live many things his whole life. It is part of being a super hero and the fastest man alive.
But nothing ever prepared him for this. In fact he does not think there is any preparation for this moment, no way he could anticipate the strange mix of pain and joy of giving his daughter away.
He walks slowly, too slowly for a speedster, holding to his daughter a few seconds more.
Damian Wayne stands at the end of the hall, dark and handsome like his father, and when his eyes fall on Irey, they fill with love and joy. Next to him, grinning like an idiot is the best man who is enjoying every second of this. (time flies, Dick was his own best man , two decades ago).
The music halts and the red heads arrive to the altar.
"Sir" Damian respectfully steps in and holds a hand for his bride.
"Take care of her" whispers Wally. Lets´her go. It hurts.
His daughter kisses him on the cheek, and smiles, radiant, happy and more beautiful than ever. The hurt diminishes and Wally knows she is going to be ok. She is loved.
Damian takes her hand. "Always"