Asking this very same question is a sure sign that something about your relationship isn't right. You won't doubt if your partner is not making you feel like there is reason to doubt. If the question, "Is my spouse having an affair?" nags you every waking moment and even before you sleep, then it's time to take action and know for sure what's for real. Here are some things you should watch for if you want to know what your spouse has been doing behind your back: