Especially if it wasn’t just a fling, but an affair that had been going on for a long time. You haven’t only been cheated on, you’ve also been deceived. It’s possible for someone to be unfaithful to you without really thinking about you at all, but an affair requires planning. Perhaps that’s what hurts most of all, the millions of tiny clues that you didn’t notice. Maybe you’d have been even more crushed if there wasn’t even a good explanation.