If you're wondering about your partner's extracurricular activities, here are five signs that he or she may be cheating.

Infidelity can be one of the most heartbreaking things to deal with in life. Not just the affair but also the betrayal of trust. Often, it’s difficult to come to the realization that your partner has strayed. Take note of these indications if you suspect your parnter of infidelity:

1) Your partner is acting differently towards you

One of the first signs of trouble in a relationship is when your partner suddenly treats you with extra affection, or starts to ignore you completely. Any change in behavior is suspect, because it implies a change in life experience. If your partner hasn’t changed anything about his or her life that you know of, and yet seems to suddenly behave differently toward you, try to find out why. While you don’t want to come off immediately accusing your partner, you do want to find out possible reasons for their change in personality.

2) Your partner becomes angry or defensive if questioned

It’s said the best defense is a good offense, so if your partner refuses to answer your questions it may be a product of their guilt in deceiving you. If you ask your partner a simple question and they immediately blow up into a rage about your “nagging,” it could be a sign that they’ve got something to hide. Remember, always approach your partner gently when asking about their life or whereabouts and don’t just accuse. There could be a valid explanation for their missing dinner or coming home late from the office. Still, in a respectful relationship people communicate with each other, so if there’s an area your partner refuses to talk about it could be a sign that they are ashamed or embarrassed at their infidelity.

3) New people begin to surface

Letters, emails, or phone calls from people you haven’t heard your partner mention before begin to invade your home. Couples don’t need to share the same friends, but they are often aware of each other’s acquaintances. So if someone new happens to call and your partner refuses to really tell you who he or she is, it may be a sign that a new relationship has begun behind your back.

4) Your partner has cheated in the past

Couples have a right to know whether their partner has been unfaithful with their current relationship, or a past one. Discuss infidelity with your partner so you know that you are both on the same page when it comes to dealing with the subject. It's true that if someone has been unfaithful in the past, they may do it again. A propensity to cheat, no matter the circumstances, is sign that an individual may use infidelity as a way to avoid dealing with issues directly. It should be noted that if your partner is not showing any of the other signs mentioned here, however, you shouldn’t automatically assume they are cheating just because they’ve done it in the past.

5) You have a nagging feeling that won't go away

Trust your gut. Often it’s that first little feeling that calls your attention to the fact that something is wrong. Don’t accuse your partner until you know for sure he or she has been unfaithful. But if you’ve got a feeling, pay attention to it.