Time Falls Away (слэш)

The Battle of New York: Tony flies himself and the nuke through the wormhole and when his suit shuts down and he starts to fall, he knows he's going to die.
But then he wakes up in an alley in Brooklyn, two strangers staring down at him in confusion and Tony is sure he is dreaming when he shakes hands first with pre-serum Steve Rogers, and then Bucky Barnes.
Trapped in 1942, Tony befriends Steve, and falls in love with Bucky but America is at war, and Bucky and Steve ship out to join the cause.
Tony knows all the stories about the Howling Commandos and knows what’s coming for the soldiers, and has to live through history as first Bucky falls, and then Steve disappears.
Tony is left alone in the 40's, crying himself to sleep in the house he had shared with his best friend and his lover.
But then he wakes up on the pavement in New York, the Hulk roaring in his face, Steve staring down at him, and he has to wonder if it was all a hallucination.
When Tony fell through the sky, did he fall through time as well? Why does Steve act so cold towards him? Were he and Bucky really that happy together?
Did it all really happen, or is Tony in love with a life he can only have in his dreams?