Lots of poly people have quiet, and simple personalities
(I`m not one of them for the record
It was more the fact that many poly people come from a background of trying swinging, but needing someting more. others have had multiple marriages. Others (like myself) also had that 'exclusive, long-term swinging friends' ideal for a few years.
I won`t kid you, the fact your husband is feeling torn, is a good indicator that you will deal with a emotional rollercoaster as growth comes about.
Your best way of handling this, is to do as much research as possible into polyamory. Keep your husband in the loop, and help him grow with you.
Knowledge is power. Have yourself fully equipped before you get to caught up with the new fellow. Curbing yourself a bit now, will be very beneficial for the future.