Is monogamy destroying more families than it saves?

My fiancee and I are in an open relationship and we have been for the past 2 years. I guess you could say we're "swingers" and we absolutely LOVE the lifestyle! I think monogamy makes NO sense. It's not natural to only want to be with one person your entire life. We have Christianity to thank for putting that thought into our head. We love each other very much and we would never leave each other, but at the same time we realize it's only normal to be sexually attracted to other people and to deny each other that satisfaction is just insanity. It's a lot more fun fooling around together as a couple, rather than cheating.