She may start spending more time away from the home, work or school.
She suddenly keeps getting called into work at usual hours, working usually late or that she has often has one business trip or the other that keeps her away from home.
She may talk to you about some really good new friends that she has made but that you have never met and keep going off to meet up with them without inviting you.
Her sudden lack of interest in your relationship, showing no or less interest in the things the two of you used to enjoy doing together, something fishy could be going on.
She is suddenly distracted, lost in thought with other issues on her mind, yet she keeps denying that anything is wrong.
Forgetting birthdays and occasions. A true and a sincere partner will never try to hurt her partner in any way and will always remember your birthday and the occasions that delight for you.
She has lots of conversation on the phone that she suddenly hangs up whenever she notice you enter the room or she is on the computer a lot and quickly closes it down as soon as she notice you have a chance of seeing the screen.
She seems more interested in fighting or arguing with you recently, and she is usually the instigator. True, every relationship has their arguments, but you can often tell when there is something else fueling them.
She may get angry about the smallest things, and resort to leaving each time this happens instead trying to sit down and discus the problems between the two of you.
She stops calling all of a sudden- How often do you speak on the phone with her? A cheating girlfriend may all of a sudden stop calling and would not even explain why she has all of a sudden stopped calling you.
Even when you call her up she would not have anything interesting to talk about or not even answer your call or even call back when she see your missed call.
She suddenly develops an interest in a different kind of music. It may be that her new boyfriend wants her to listen to that type of music or she is doing it to please her new lover.
Her sudden interest in her appearance. She becomes more attentive about her looks, the clothes she wears, perfumes she uses and her hairstyle may be changed. She might change from conservative to more provocative.
There will be distance in your intimacy and reduction in your emotional attachment. Your girlfriend might deny holding your hand in public. It may be a proof of her emotional relation with another man.
Meetings and plans will be cancelled without explanation and she will show less interest in those activities you both enjoyed together. Her interest in the activities that you had enjoyed together previously can be seen to be reduced. You might notice a series of unexplained cancellations of plans.
Your girlfriend will avoid talking to you, and spend less time with you. There will be a communication gap. There may be less communication between you. Your girlfriend may tend to avoid talking with you. She may not be available to spend much time with you.
Your girlfriend spends more money without an account for her expenses. Your girlfriend might be spending a lot of money, because people who cheat always meet at hotels or restaurants. She may not be able to account for the expenses.
If your girlfriend avoids being near you and goes to another room to attend phone calls, and if she receives calls at odd hours in the night, then it is a sure sign of cheating.
You will notice that your girlfriend needs privacy, especially regarding her cell phone. She may avoid answering the phone when you are nearby. She may go to another room to attend the call. Getting the calls at odd hours can be important sign of cheating.
Your girlfriend will get angry unnecessarily and will find fault in you often to hide her faithlessness. There will be a change in her behavior. You will experience that your girlfriend’s behavior is suddenly changed.
She starts criticizing you and gets angry at the things that never used to bother her before. She may be trying to emphasize your faults in order to justify her faithlessness.
To spend less time with you, she might start a new hobby, or encourage you to go out with friends or go on a trip. Your girlfriend may encourage you to spend more time with your friends or to go alone on a trip or to a movie.
She may start a new hobby or may talk about the movies that you had never seen together, following the hobby and interest of her new boyfriend.
Your girlfriend might have changed her email address and taken a new one which she won’t tell you. She might be possessive about her mobile phone or her lap top which she won’t let you see, because she might be having secret messages.
Your friends might know that your girlfriend is cheating on you, and they might behave strangely when they are with you. You may notice that some of your mutual friends start acting strangely when they are with you, they may feel uncomfortable with you.
She has stopped answering your calls, or every time you call her, she seems distracted or that she could not care less about what you have to say.
You get a feeling that she no longer wants to hang out with you and all of a sudden, she’s got unexpected visits from cousins or relatives that you’ve never heard before and she uses that as an excuse to avoid seeing you.
She no longer wants to do the things that you two used to enjoy doing together, like going to see a movie or go for a walk or simply enjoy each other.
If any or all of these signs are present, then it is time that you talk to her. If she denies anything but you are still suspicious, then you can use technology to your advantage and catch her.
She does not tell you all about her day and she seems more distant and closed off.
Your girlfriend has a sudden renewed interest in her appearance such as new and different clothing, hairstyle or weightless.
She starts to take up new interests that are out of character for her.
Your girlfriend changes her schedule. She may start earlier, end later or have new requirements such as dinners and late meetings.
She closes program windows on the computer as soon as you are near.
Your girlfriend starts to leave the room to take calls from her cell phone.
She starts to use or changes her use of perfume.
Your girlfriend starts a new habit of showering when she comes home.
She has recently become more argumentative or critical and has no obvious cause such as financial, work or her health.
Your girlfriend provides abnormally vague reasons for being late.
She becomes evasive when you ask about her where she was and what she did during the day.