A woman who's never been known to read more than a magazine but who suddenly starts trying to wade through Proust might also be the subject of slight suspicion.
Unless you have a long history of unfounded jealousy or paranoia, then you're almost certainly right.
Sometimes betrayers are so turned on sexually by their new lover that they start having more sex, rather than less, with the person back home.
General behaviour : They may become more secretive.
If you start questioning, they may well reply: `Get off my back. Appearance : People who are having affairs usually start to look better, partly because they're paying more attention to their appearance by exercising or buying new clothes, but partly, too, because it's impossible to hide the happy flush of sexual and loving excitement that infuses them.
Your intuition: Perhaps the most tell-tale sign of your partner having an affair is your own intuition.
Their conversation may feel slightly different and they may suddenly entertain new ideas that seem to have appeared from nowhere.
The man who suddenly declares that he's heard that Evening Primrose Oil is good for long life, and starts taking it, is a man to watch.
But we are all human - and so, of course, are our partners. So how can we spot if our partners are having an affair?
There are five tell-tale signs: Conversation: Our partners may mention the name of a particular woman or man more often than usual, sometimes repeating what they have said.