It wasn't that Barry'd had a giant crush on Captain Cold back home. He'd noticed he was attractive, of course, and he'd enjoyed their banter, but it had never really moved beyond that. He'd been too confused by his feelings for Iris, and then his fledgling relationship with Patty to give it too much thought. He'd never really considered the idea that he might want something, be it sex or a relationship, with more than one person until he and Iris had talked about it here. With that knowledge, it was just easier to acknowledge that he was interested in something with Snart.
Especially since the more he learned about the older man, the more fascinating he found him. His morality was so strange. He could kill people and steal things, but he wouldn't cheat on or with someone. Not that that was a bad thing. And not that Barry was cheating here. He'd talked to Iris about this very thing. And he appreciated that Len didn't want to hurt her. Not hurting Iris was kind of a big thing for him.
And then there she was. He couldn't help smiling as she spoke, a natural reaction to Iris's presence. "Hey," he responded. "You don't have to. Unless you want to." They'd never discussed the particulars of how to handle this, beyond honesty and consent, so he wasn't sure if Iris wanted to see this play out. But he was never going to exclude her from any part of his life.
"You could ask her yourself," he told Len. "But we were being serious. We actually discussed this...I mean, you...already." He glanced over at his girlfriend. "Iris, you'll be happy to know he refuses to kiss me until he's sure I'm not cheating on you. Isn't that...good of him." Why yes, he was making another 'Leonard Snart is a good person' comment.