My husband has expressed a desire to get involved in "swinging," I am not interested in this for many reasons. My problem is I cannot find anything negative about this lifestyle anywhere. I know that there must be an increased incidence of stds and divorce, but I cannot find statistics to support this. Is there any where that I can get an honest answer to my questions? Every web site or article I find paints a rosy picture that is too good to be true. 

I'm not sure where you could get access to actual research on the issue, but I can tell you from the clients I see in my private practice that injecting one or more partners into a relationship does cause jealousy that can break up a marriage. I am the first to admit that I only see people for whom these extra parties cause difficulties. If swinging has not affected the relationship of a couple, they're not going to make an appointment to see me. But jealousy is a fairly universal emotion, and while there are certainly people who can overcome it, my unscientific guess would be that there are many more who cannot put their jealous feelings aside so easily. And sometimes it's the partner who wants to get involved in swinging who winds up being the one who feels the most jealous. 

Now I don't think you need any hard evidence to say no to becoming a swinger. If it's distasteful to you, for any reason, your husband should respect your wishes. If he persists in pestering you about this, then the two of you should see a counselor to see if there are any underlying issues that would cause him to pressure you.