Stephen shuts his eyes as he activates the time stone and the sounds of arguing around him fade away, as does the hideous landscape of Titan and he dives through the power of the Time stone watching timeline after timeline go past. There’s one that seems to call Stephen in to look at it more closely.
The timeline he enters is complicated full of different and constantly changing emotions and he reaches out and begins flipping through the important events. He and Tony lose to Thanos, the three of them survive being dusted by some miracle and are able to make it home thanks to Quill.
The world has lost half of the people on the world and there is of course sadness everywhere they look.
Slowly they move on, people make their peace with the death of their loved ones and Stephen and Tony work to keep the world turning and slowly Stephen works up the courage to tell him how he feels.
Their first kiss is under the stars in a planetarium, the darkness hiding them from the prying eyes of the public and letting them finally be themselves.
Stephen watches as they kiss, fight, breakup and makeup and wash rinse repeat. He watches one of them comfort the other when they have a nightmare and soft kisses when one or both of them are feeling sad and he watches as they comfort Peter Parker and guide him through the life that he now has.
Five years after the fight on Titan Stephen sees himself, ring in hand, asking Tony to make him the happiest man on Earth and Tony smiles as he says yes and puts the ring on his finger and the kiss they exchange seems to go on forever.
Their wedding takes place a year later and Tony looks gorgeous in the nice suit he wears as he walks down the aisle and Stephen thinks he might cry with how beautiful he looks and he is so choked up he can barely get the required words out of his mouth, but after a few minutes he does and he watches Tony‘s mouth stretch into a beautiful smile as he says the needed words and they kiss when Rhodey tells them to.
Their life together is full of joy and happiness, they have dates under the stars and on other worlds, Stephen tells Tony all about the different spells he can do and even shows some to Tony and Peter.
Ten years later, on their tenth wedding anniversary, Tony finally tells him that ever since the events on Titan. Ever since their failure on Titan, Tony has hated the fact that he failed and Stephen already knew. Already knew that Tony regretted not being able to do better.
Stephen holds his husband against his chest as they dance under the light of the planetarium and presses kisses to Tony’s head.
Stephen jerks himself out of that timeline when he sees another one begging for his attention and he takes a deep breath and dives into that one as well and he watches himself hand over the Time Stone, this time both he and Peter turn to dust. He watches Tony mourn the Spider child and fight and struggle to make it home and then when he does he watches Tony cling to Pepper his first love and h watches them settle down and have a beautiful baby girl that grows into a young girl just as adventurous as her father and Stephen can’t help but smile and watch her grow.
He watches as the Avengers approach him about time travel, he watches Tony turn them down and then he watches as Tony works all night without rest and somehow manages to come up with a stable form of time travel.
Stephen is very proud.
He watches them track down the stones throughout time and bring them back. He watches the snap and his and the other people who were snapped reappear and he watches them fight for their lives and the lives of the people around them.
He watches as Peter and Tony hug and then he watches him and Tony talk about this being the one timeline where they win and he watches as Thanos gets the stones once again and he watches with bated breath as Tony tries to stop him only to get knocked away and he winces as Thanos snaps.
A smile breaks out on his face as Thanos finds the stones missing and then he sees Tony with the stones in the gauntlet of his suit, his human Tony with something so powerful it hurt the Hulk of all people, and he watches the man he now knows he loves snap his fingers and the light is nearly blinding and Stephen watches as Tony collapses and fights to stay conscious as Thanos’ army and the Titan himself turn to dust.
He watches as Tony’s loved ones, Potts, Peter, and Rhodes gather around him and say their goodbyes.
He watches as they all stand by the lake shore as Potts sends his first arc reactor out to sea and Stephen presses his hands to his eyes to keep from crying.
“Strange?” He hears Tony say and he opens his eyes and Tony is there to keep him from pitching forward and Stephen sucks in a couple of breaths and Tony is saying something but Strange isn’t listening.
He has a decision to make and he knows which one he wants to happen and which one the world needs to happen.
He just wishes it didn’t have to happen.
He can either live a life full of love or kill the future love of his life.
The pain in his chest increases and looks at the man he can either sentence to love and sadness or love and death.
Stephen makes his choice.