Sure, details were important. That was true. But Tony didn't have them, not really -- just the base ones, the entire picture that was still a little blurry. Even if Steve explained it'd still be kind of that way -- and it would stay so until Tony actually lived it himself, or caught a few memories here as well. He wasn't sure he wanted either, even if he knew at least one of those things was inevitable, and that he wouldn't (couldn't) regret it while it was happening.
"Hey," he repeated, his other hand brushing through Steve's hair. It wasn't like him, not really, to hide his face. Not even when he was going through a lot. So this was ... off putting. Tony wasn't sure how to handle it, what he could possibly say in order to alleviate some of this pain that Steve was so obviously reliving. Living for the first time? Tony wasn't sure how to categorize that.
"You're going to have to tell me," he said finally. Because he could say Steve had nothing to be sorry for, and he could believe it all he wanted, but if he didn't have the details Steve had, Tony'd never be able to convince him of it.