Friendship - yes AND no. Can I play with people that I'm not friends with, yes. Do I want to keep everyone at arms length and actively PREVENT friendships? No.
J. has the same issue when we first started swinging. He wanted to keep everyone at arms length and just consider them our living, breathing, walking, talking, sex toys. Now, we have one couple that we're actually really good friends with. We hang out. We go shopping. We go to lunch. We talk to each other about our families and our problems. A lot of this has to do with the fact that she and I (I am the F half) are basically the same in many aspects of our life and we clicked emotionally from the first meet. I can trust her, and she knows that she can trust me. And she's sexy
It's great. And our single M that occassionally joins us has been J.'s best friend since elementary school.
Your wife may need the friendship aspet. Why is that so scary? In my honest opinion, it sounds like you're terrified of putting yourself out there and being social. You're willing to be sexual, but forget anything else. True, some couples are out to just "use" you...but many are really really good people too. If you find a couple that your wife really likes, maybe you should put yourself out there and try to be friendly atleast, if not friends.