Thank you both for the welcome.
You're right, I should be-and am!-very thankful for my husband. He has been sensitive to my feelings from the beginning.
He informed me when we started dating (in 2005) that he was poly-though the other relationships he was in at the time didn't last too long after we met. Since then has waited for me to become more comfortable with his lifestyle.
It took me five and a half years and a wedding, but I finally became receptive to his ideas.