I am a big fan of the book Sex at Dawn, and also use it in my show. (which I am going to link to now, because, damn it, it's about polyamory! http://tinyurl.com/LUSTANDMARRIAGE
For me, learning the scientific basis of the desire to have more than one sexual partner helped me feel a lot better about my husband wanting to be with other women. I was able to get over my "what's wrong with me?" story. Super useful. I've met Chris Ryan a few times (helped produce a talk he gave here in Portland) and I wish he'd written more in the book about how he uses this information in his own life. That's part of why I wrote the show. (And part of why i love this forum!) I want to hear more real life examples.