After CA- The Winter Soldier:
Steve is trying to help Bucky adjust to the modern world by using Newspapers from over the years. But one article sends Bucky running from the apartment. When Steve finally catches up to him Bucky finally confesses what sent him running, and what really happened on the night their friend Howard died.
And after, Steve does his usual meet up with the Avengers, and he realizes his best friend killed Tony’s parents. He agonizes over what’s worse—betraying Bucky’s trust by telling Tony the truth, or betraying Tony by lying by omission. He can’t choose—realism vs optimism, the people he lost vs the people he was given, his old life vs his new life. He’s always stuck there, right at that crossroads. He can never choose.