Having an affair goes against everything we are taught in society, primarily that we should only love one adult person at a time.  Such socialization makes it impossible to share our love for more than one person with others.  The only way it has been possible for me to live a life that is not crazy making, is to surround myself with close friends who know about my choices and who do not judge me for them.  It makes it a lot easier to live in my reality, rather than a hidden reality and a false public persona.

Such a life is not possible for everyone, or even for most, but I highly recommend it if one can find a way to negotiate it safely.