Is it a "cop out" to cheat on someone and then not tell them what you did?

I've heard so often "I can't tell them I cheated on them b/c it would really hurt them." That seems so hypocritical to me. If this person was so concerned about "hurting" their partner, they probably wouldn't have cheated in the first place; correct? Does anyone else think this line is simply a rationalization b/c a person doesn't want to go through the "hard work" inherent in being honest with someone??? Just seems to me that by not being honest you're cheating yourself out of a truly intimate relationship by keeping secrets. Secrets = Zero Intimacy ... Am I wrong in thinking this way??? Can a marriage actually survive with this huge secret and dishonesty between partners?