How will you know if your partner is cheating?

Easily when I don't have one...

when u catch her in bed with someone else

actually, it's not that easy to tell. some men are really great pretenders. they are good secret keepers. my ex boyfriend for 8 years was constantly cheating on me. but i knew it so late already. i befriended her housekeeper at home. and she tells me things... who my ex brought home since i live away from him. and after getting evidences, i finally got the courage to break up with him.

Well, there are alot of signs to see if your partner is cheating or not. Maybe she starts disappearing and doesn't really have a reason to where she's disappearing to.. and people start smsing her and calling her and she's like really suspicious about it.. stuffs like that etc.

I will find it easily if he cheated me his face will change he will blaber some think.

I do belive that you should trust your gut-feeling. If u feel something is wrong it most likely is! Also look for signs . He/she doesn´t show you as much affection, is gone alot more with strange excuses and so on!