It is not every guy that will cheat on you. Many of them are really faithful to their partners. Not every guy will cause you pain, not all of them will break your heart. Some will actually show you love more than you deserve.
Not all of them will make you sad; some will try everything within their power to put smile on your face. Not every guy wants to sleep with you. Some are not just infatuated; they love you and reallywant to engage in a long-term emotional commitment with you.
So, there is no point saying that all guys are the same. Instead of holding this erroneous view, say that all the guys you have dated appeared to be the same. However, I think you have not really tried all of the guys available for dating.
If someone breaks your heart, cool down and move on. Sooner or later, you will get someone who will pamper you like a succulent baby, who will treat you like a pretty damsel, who will serve you like a queen, who loves and kisses you passionately, who will show you real and undiluted love, who cuddles you when you are angry.
Some cheat because they are not getting what they deserve from their partners; not just what they want, but what is due to them. It could be love, affection, care and so on. But still, this is not enough reason to cheat, because cheating is a choice.