Carrie Bradshaw and John James “Mr. Big” Preston were never the most honest couple on Sex and the City. The on-and-off pair had one of the most frustrating yet riveting dynamics on the HBO series, misleading each other about commitment issues early on, then cheating on their partners because they simply couldn’t stay apart. Even after their wedding, which happened only after Big left Carrie at the altar in the first movie, the relationship wasn’t clear-cut. Carrie kissed Aidan in Sex and the City 2, after all.

Against all odds, Big (Chris Noth) seemed to stay faithful to Carrie (Sarah Jessica Parker) during the stretches when they were exclusive. But one Reddit theory argues otherwise.

After one fan expressed amazement that Big never cheated on Carrie, another begged to differ, outlining a theory that he was unfaithful after the pair got back together in Season 2. Because the show is told from Carrie’s perspective, the argument goes, she never discovered his dalliances, so viewers never saw them either.

The evidence: Big refused to give Carrie a key to his apartment and didn’t want her leaving personal items there, two signs that he still wanted to use his home as a bachelor pad without getting caught. He also acted suspiciously at Miranda’s friend’s wedding, refusing to sign the card or dance with Carrie and taking calls during the reception, possibly from another woman.

When Carrie tried to arrange dinner with Big and the girls (Miranda, Samantha, and Charlotte, duh), he flaked at the last minute with vague excuses, only to show up at the end of the night. Some Redditors don’t buy that he simply changed his mind. Maybe he had plans with the other woman, who then canceled on him.

And of course, Big moved to Paris. Carrie wouldn’t shut up about it, which is why the line became one of the internet’s most enduring memes. But the casual way he broke the news, with so little notice, also raises alarm bells. For a man who was seeing other people, moving abroad might not have felt like a big deal.

On the show, these moments are chalked up to Big’s fear of losing his independence or admitting how deep his feelings for Carrie really were, not a desire to date around. But this is Mr. Big. He cheated on both of his wives before Carrie, the first by his own admission and the second, Natasha, with Carrie, and he wasn’t shy about seeing other women while courting Carrie after they first met.

One reason fans believed Big’s feelings for Carrie were different is that he never strayed while they were a true item. But maybe he did anyway, because it’s clearly in his nature. And in hers, but everyone already knows that.