You've been happy in your relationship for a while but something is starting to feel off.
Your intuition is most likely right if you're a woman, according to private investigator David King who said the female gut instinct is right 80 percent of the time.
1. Behavioural changes
Men and women are equally likely to cheat, but women are most like to engage King's services after spotting suspicious signs.
King said that a man who is playing around might act differently:
Men start to take a bit more care.
They might work out a bit more, or be clean shaven more often, or start dressing a bit better or smelling nicer.
A particularly unpleasant sign that King has noted is rage.
If men are guilty this can manifest itself as anger.
Husbands will often manifest anger into a relationship, and this can sometimes work as a way to get out of the house.
2. Strange phone use
The modern world gives us tools like never before to discover cheating - and it is tricky not to leave digital traces of an affair.
You might see a message pop up in your partner's iPhone that looks a bit weird, or he is more protective of his phone.
He may have put a password on it, whereas he never needed one before.
3. Excuses for not being at home
Yet another late-night tennis session when you thought they hated sport?
Not a good sign according to King, who recommends being wary about any strange outings.
Men will come home late or go out without their partner when they previously would have taken them
4. They are not present
The Daily Mail was also told by top experts to mistrust a partner who's just not present - even when they're physically there.
Being off in their own world all the time probably means they are not fully invested in yours.
5. Accusations that you are jealous or crazy
The same experts psychologists warned that shifting blame onto you can be a diversion tactic.
After all, attack is one of the best forms of defence.