I've been in an open relationship with my partner for almost 4 years. Neither of us really believe monogamy is necessary for a successful relationship. For some people monogamy works best, and for others it doesn't. Some people work better within an open or polyamorous relationship, like myself and my partner.

If you want to learn how to build a successful open relationship, I highly recommend reading this book cover to cover (and maybe have your wife do the same, so you're on the same page, so to speak):

http://www.amazon.com/Opening-Up-Cre...9211397&sr=8-1

And remember, there's no one "right way" to have an open relationship... but there's definitely a wrong way! Honesty and communication are absolutely crucial to a successful open relationship. I know I can trust my partner more because he is honest to me about who else he sees (and likewise, my partner trusts me because I am honest with him about who I see).