Chris Hart: You’d never guess from the way people talk, but women cheat just as much as men. Only they’re way more subtle and tricky about it, and don’t get caught nearly so often. At rock bottom, guys cheat because faithful men have far fewer children than cold, heartless seducers.

So the genes that make men into cold, heartless seducers in the first place keep getting passed around. But that doesn’t work for women, because they have about the same number of children no matter what. So what does make women cheat? Or start relationships with married men?

Biologically, one reason is to avoid having all her eggs in one basket. Having a baby by another man spreads a woman’s genetic risks — so long as her husband never finds out. Another reason is that women want their children’s fathers to be winners!

Ask any woman: “Would you put up with a loser?” and the answer’s always “No!” But all that means is that there aren’t enough good men to go round — which is why so many rich guys have mistresses and girlfriends.

And then there are the emotional reasons why women cheat. Like she’s in a brand new relationship and really likes the guy, but he’s not quite ready to be exclusive? Really bad strategy, mate. Because while you’re wasting her time, she’ll wander. Or maybe you’re spending way too much time on other stuff?

So instead of the attention and romance she needs, she’s getting bored and frustrated. Believe me, if you aren’t having fun together, she’ll be finding it somewhere else.

Watch out

Perhaps you’re forever forgetting her birthday, anniversary or whatever? Or you spend more time with your mum, or at work, or with anyone else other than her? Watch out. Or she’ll soon be looking for someone who will put her first. Or maybe she feels your relationship isn’t going anywhere. Couples must keep growing closer or they drift apart. So start marking time, and she’ll soon start straying.

Perhaps you have way too much baggage? Psycho ex? Meddling mother? Weird friends? Whatever it is, there’s nothing more unattractive than a man with lots of baggage. Even if you’re spoiling her something rotten. The same is true if you’re not delivering the loving she needs. Or you’re always fighting. Or you’re heavy with her.

Because often as not, today’s independent woman has a guy she can call on. He knows she’s in a relationship, but he’s always available anytime you aren’t acting right.

Plotting revenge

Or you’ve cheated on her. Even though she’s taken you back, don’t think you’re in the clear. She’ll smile and act like everything’s normal, but behind that smile lies a broken heart plotting revenge. So don’t be too sure that your lady would never ever cheat on you. She really might. In fact she’ll only stay faithful while you play your cards right.

Drop your guard and she’ll stray. And always when you least expect it.