There are many things our partners can do that can cause us to question ourselves. However, few things cause this to happen more than cheating. Dealing with a cheating spouse is difficult enough, but the almost automatic response to question ourselves just makes it even harder.
When dealing with a cheating spouse it's normal to ask how and why this happened, and in trying to answer those questions to assume that it has something to do with us. This line of thought, asking what we did wrong to cause the cheating happen, can take us down a bad path if we're not very careful.