How To Find Out If Your Boyfriend Is Cheating On You

Less contact. Otherwise, there are no ways to know - if you don't want her to know- don't mention it, and she doesn't spend enough time with you to see your body language or changed habits. Oh, and the gut feeling can play funny tricks when on a long-distance relationship, so mind that.

• If you have been phoning or emailing each other and he contacts you less and less. If he was making an effort on his holidays or long weekends to come see you and he has stopped doing this, then it sounds like he has lost interest. Long distance relationships are tough to hang onto and please take solace in the fact that there are so many people who have long distance relationships that break-up. I would simply go visit him and see what is up (if you can) and communicate one-on-one and find out where your relationship stands. If he's ignoring you, then you must move on. There are a lot of other nice guys out there.
• Two words: Unavailability and Inconsistency..these two things ALWAYS mean something is up.
• Trust your intuition. I didn't think my boyfriend would ever cheat but there was this gut feeling that wasn't there before. The signs you should look for:

1. His contact pattern with you changes. He doesn't instant message, call or send emails as often (or he starts sending more of them to cover up) or changes his routine times for doing these sorts of things, ie. he is unavailable when he used to available. Rather than wanting to spend all night chatting he has to cut his conversation with you short to "do something". I noticed my CBF's IM messages to me were lagging when we were online. I found out it was because he was talking to me and someone else at the same time.
2. He starts talking about new places he "checked out on his own" or with new "friend(s)" when he is really not that kind of guy. Or, he starts talking to you about topics that never interested him before and not related to his work but is now compelling to him.
3. He stops sharing details about his life. For instance, you have to draw out who these "new friend(s)" are and how they met etc. You may also notice when you are in town you never get to meet the "new friend(s)" because he wants to spend 24/7 with you (not true, but you will want to believe it). You may also notice that he doesn't take you to the "cool place" he discovered when he was out and about on his own or with his new "buddy". He gets angry at you or accuses you of controlling, snoopy or being bossy when you ask about his new friends. He reminds you that he is allowed to have friends that are just his friends not yours.
4. He no longer wants you to tag along to the grocery store, to get his hair cut or other little errand (you will find he was off making a call to her or trying to meet with her). Before he wouldn't dream of leaving you at home alone.
5. Rather than begging you to come down and see him he encourages you to catch up with your friends or work over the week-end or tells you that he has to work all week-end himself and he won't have much time for you if you come down so you might want to think of staying home (truth - he has a date with someone else).
6. When you come down to see him he has spruced up his place or asks you to help him pick out some new towels or plates or some other housekeeping item he has never showed an interest in before (he wants to make a good impression on the new woman). Ditto on the clothing front. If he has invested in new clothes and is on a diet chances are pretty good that he isn't doing it to look good for you.
7. You notice new bath products in the bathroom. New linens in the bedroom. Fresh flowers already in a vase looking a couple days old in his house. Or things that you placed in the bathroom are moved or no longer there.
8. His computer now has a password when it didn't before. You notice that he now wipes out the history files on his computer (this is to make sure you can't follow what he has been up to - can you say dating web site). He switches the computer screen when you walk into the room or tries to hide the screen from you. He turns his computer off or no longer wants you to use it to surf or check your email.
9. His car smells different or he starts using cologne or buys a new scent when he never used the stuff before.
10. He starts being short or critical with you over little things. Or asks "why you don't ever ....." (fill in with something the new woman does he likes or even dislikes).
11. He makes sure you have all your stuff before you leave. Before he began cheating my CBF could care less if I left something behind because I would get it another time.
12. He switches tenses. When he used to talk about the two of you he is now just talking about himself, ie. "We should go to..." is now "I should go to ...". Other examples: "We should get a puppy" is now "I have been thinking of getting a puppy" or "Where should we go on vacation this year" is now "I am thinking of going to ..." or "Our house" is now "My house". Little subtle and not subtle shifts in talking.
13. He comments on you losing or gaining weight when you have done no such thing. (Someone else he has been grabbing onto is bigger or smaller than you.)
14. He likes clothes on you he used to hate on you. For me it was pointy toed pumps. My CBF used to hate it when I wore them and asked me not to wear them when we went out together. After he started cheating he told me he loved pointy toed pumps and I should get a pair.
15. He starts accusing you of cheating on him when you are not together. This is reverse psychology or him trying to sooth his own. He may also start complaining more than usual about the long distance thing. He may encourage you to move to where he is or question where the relationship is going to. Instead of wanting to seriously talk about it though he quickly changes the topic. Again, this justifies in his mind his cheating.
16. You catch him in a series of small nonsensical lies.
17. He seems to have less money to do things with or doesn't want to go out and do things with you. (He is spending his money on dates with the new woman and is either pooped out from all that entertaining or doesn't want to risk being scene in public with you.)
18. Your gut/intuition/6th sense whatever is screaming at you something is just not quite right.
19. Please be reminded that they will lie, lie, and bold fast lie even though you may not have ever known them to be a liar about anything ever before. They will call you paranoid, psycho, jealous, unreasonable and just crazy because they love only you. I hit my CBF with cold hard irrefutable evidence of his cheating and he still lied about it.

Well the answer above is good but coming from a guy id say my friend told me he was cheating and i always went over 2 his house when his gf came over i had 2 hide under the bed or in the closet he truly did oblivious lieing. u should be able 2 tell if hes lieing. 

1. When he acts different then usual. 
2. When he thinks its all about him and refers to things that only has to do with him. 
3. When you ask him a question about what he is doing, then he answers you with another quesstion. 
4. When you tell him you love him and he hesitates to answer. 
5.You catch an STD from him-disease - 
sexually transmitted 
6.Lube all over his arse-affair with another man 
7.Too many calls from a number registered under a man's name-a trick or 
Too many calls from a family member.Go through his mobile for these numbers when he is in the shower.