It was a surprise but maybe it shouldn't have been. He was Tony after all and even if he didn't talk about it at the time, he remembered things, stored them away for later. They hadn't spoken about it, hadn't needed to, they'd gone onto other things like Tony's death and marriage so Steve trying to date hadn't seemed like urgent discussion fodder. So maybe that's why he was surprised.
Maybe that or because Tony was so quick to deflect, talking quickly and taking his pants off both which he knew Steve found distracting. "Well you are pretty impressive, I'd say you could manage it," Steve agreed as he propped his head up in his hand, his hand resting on Tony's chest so his fingertips could drum ever so lightly against the reactor.
"No better problem solvers than you, someone tried maybe," Steve shrugged. He could see his face now, hear the arguments in his head about why Steve was so distant, always with both feet out the door. "If you want to ask, you can ask me anything," Steve said softly.