Sex with couple and female's best friend

OMG I am not a very jealous person and very giving too. My bf and I have been swinging for almost 3 years now and what we have shared and experienced together has been totally awesome. Yes, there is however, but most of our experiences have been with a very dear and trusting friend. And maybe I am making a big deal out of nothing but, since our encounters with my best friend, both her and I kind of feel that my bf has somehow planted in his head that my best friend is also a part of us too. What I mean is a few times when she comes over and stays with us, she wants to explore out in the night for some action, so now my bf has been actng kind of like he is upset over the fact that she goes out or even who she is talking with. He hates the fact that she doesn't just plan her stay with us period. When she gets here they chat like they are best buddies and I just hang out listening. She dresses up and his eyes fall out of his head and he proceeds to give her compliments and takes pictures like there isn't any tomorrow. And when nothing happens witht he 3 of us he gets ugly acting. When she isn't around us he comes home asking million and one questions like " did you hear from your friend today, when is she coming over again, or if i have talked to her then he wants every detail of our conversation" it's endless with his couriousity of wanting to know things about her. It has made me feel uncomforable at times so I talked to my friend about it and she was feeling kind of the same way, as if he thinks at times that she is also his gf. Just what am I facing here I have never experienced this before with someone and don't know whether to stop including her in our sex life now or not. Or if maybe i am just over reacting. Help me with any suggections or advise you may have.