what i wish id told her before the swap last weekend...

ok so this is gonna sound daft but we did a full swap on saturday for the first time in months and it went... fine? but theres this thing i wish id said before we started and now im chewing on it. basically i had a feeling about the other bloke being a bit too into her n i didnt mention it cos i didnt wanna ruin the night. now its monday and im stewing and shes asked twice if im ok and i keep saying yes... how do you bring up "i had a gut feeling and i ignored it" without it sounding like an accusation of her? cos its not. its me being annoyed at me really...