Thank you all so much for the great feedback & advice.
I was able to address my concern. Evidently I need to quit over thinking things & act the same as I would in any other intimate relationship as well as stop basing my decisions on my experiences in the swinger culture.
It was no big deal. His response to my concern was "of course" and he shared as I had originally thought they are not seeing anyone else & are enjoying where things are going with us. He has responded to any question or concern fantastically & has reassured me that as awkward as some questions are to ask its important to communicate. So this whole fear of talking about certain things is completely mine.