Of course he'd worry about stuff like that, it wasn't even really something he wondered over why he'd have done that so much as he'd needed something to say that was safe and luckily it was pretty obvious Natasha understood that.
Well. It was obvious that Natasha understood Tony in general. There weren't a lot of people that he would allow himself to break down in front of -- the list was less than a handful -- but Natasha was on it. He knew she wouldn't use it against him because there were some wounds you simply didn't tear open again to make a point. She'd keep this between them, and she would let Tony work his way through it without judgement.
Her shoulder was solace, the hand at his neck a reminder that he wasn't going through this alone. Of course she'd understand. It took him a little, and even though he was quiet about his breakdown and tears, his shoulders trembled and surely Natasha's shirt would get the brunt of his tears.
This was a terrible truth. Painful in a brand new way for a man who'd been positive there couldn't possibly be any more surprises on that front. But when she offered the choice of giving up or continuing, Tony didn't even have to think about it. "Keep going." It wasn't easy for Natasha either, it was obvious, and so Tony squished himself closer until they were as close as could be, a support system built by two people who were rarely the touchy-feely sort.