I have to agree with Quath. His comments are a lot wiser than the hot headed response I was tempted to write. A number of people on this forum have pointed out that working on polyamory relationships tends to magnify and intensify the problems and pleasures in existing relationships. If you and your husband get into the habit of communicating very honestly and effectively to deal with your new relationship, it may well deepen and help your existing marriage.
I wish you the best! Warm regards, Rick.