I thought I'd throw in my story for you as well.
John and I have been ploy since our inception in October of 2007, we've had our trials, but we are still poly and together.
R, who I will kick things up with sexually again very soon, and I have been best friends and some-time lovers for about 12 years now. He is going to try to join our family later this year and we both know that if it doesnt work, we will go back to being best friends again. We've been through several periods where we werent sexually involved, but our feeling for each other have never changed over the last decade plus.
The key is communication, both active listening and being able to communicate your needs and wants.