Fact is, swinging isn't for everyone. Heck, it may not be for most people. If anything, all I hope is that this forum and/or thread shows your wife that swingers can be and are in loving, committed relationships.
She's absolutely right. We're all biased, based on our own experiences.
Food for thought, though: The people who typically say that swinging isn't harmful to their relationship are those who have done it. Those who seem to find it inherently harmful are usually those who - surprise - have never actually been swingers.
I think you'll be stuck looking for a long time. There aren't many who could be considered "professional" swingers, and we're all independent in the sense that we don't have any agenda other than expressing our own experiences. Really, there is no such thing as a "Consumer Reports" for swinging - you pretty much have to look at what people tell you about their own experiences and see how much of it applies to your own situation.
Honestly, the only experts on your relationship and suitability for this lifestyle are you and your wife. Don't look outside, look within.