[The Funky Llama]

I would bet/call the turn. As people said this prevents him from taking a free card with a flush draw (or an overplayed A4 that decides it wants to check...this happens), plus you lose less when behind since you shouldn't be folding to a 3bet after you checkraise.

Also, it is not at all impossible that CO has 2 pair on this board, even something like 92s or 54o. I play these games all the time and those hands wouldn't really surprise me and against them you have more outs, as you know.

You should try to avoid making heroic folds against unknowns in aggressive games, especially when you will be getting something between 17:1 and 19:1 and often have 2 outs.