I
First time was at his parents's funeral. The guilt for feeling relieved didn't stop him from enjoying breathing his first breath of freedom.
II
Next time, running from the third abusive foster family, the feeling of freedom in his lungs was only slightly tempered with the fear of the future.
III
Being left for dead by Barney and the Swordman made his lungs hurt with the air of betrayal. And maybe, just maybe, his heart was in pain too.
IV
When a suit shoot him, too tired to run after years living like a criminal, and instead of killing him offered a job, a chance to do something good, the warm air full of hope might have brought tears to his eyes.
V
When some years later the same man who shot him is placing a ring in his hand and kissing him, both of them release puffs of laughter full of love while the small crowd of friends cheers.
+1
When the blue fades, and Fury hands him his husband's ring with nothing more than a apologize, he feels like he is dying. There is no air anymore.