Human beings are inherently flawed, and this is what causes much of the grief that we see in the world at large. Even if you are with someone that you feel would never hurt you in a million years there is still the likelihood that they could be tempted in one way or another and this might just leave you heartbroken in a way that you would never have thought possible before regardless of anything else you had ever assumed based on the way you actually do things.
If you partner cheats on you then this is something that would most likely make you want to end the relationship and facilitate a greater understanding of what caused such a thing to occur. Suffice it to say that getting over infidelity is never easy, and it will require a lot of effort on your part before you can say that you have fully healed.
Part of getting over infidelity has to do with realizing that you are not the person that is at fault here, regardless of what you may be thinking. A person cheating has nothing to do with who you are as a person, but rather the kind of person that they happen to be.
Cheating is never the fault of the person that was cheated on, it happens because the person that cheated wanted the thrill of the experience. Hence, you should never feel guilty if you got cheated on because this will only make it all the more difficult for you to get past this trauma and become who you actually wanted to be. This is the most important thing to note when you are getting over such a thing.