Thanks everyone! This is really helpful, especially your situation, LR, as that's kind of what I was thinking would be really awesome, just somehow it didn't seem realistic to me. The fact that there's a successful real life example right here changes my perspective on that.
Also, sorry for my super slow responses. My husband finally gave the go ahead on trying out this polyamory stuff a few weeks ago, and school just started back up for me, so I've been quite busy and preoccupied.
I find I have a new challenge as far as the relationship dynamics go, though. What I was hoping is that I would be able to direct all that warm, fuzzy NRE at both relationships and improve my poor sex drive with my husband and everyone would be happier all around. Instead, I'm finding that I have a serious case of puppy love in my new relationship and the fantastic libido that goes with that, but in my marriage it still isn't there. I feel more willing to do some things for my husband, like oral sex, which is very focused on him and what he usually prefers anyway, because of the awesome trust and freedom he's given me, but I find myself avoiding regular sex with him, which is what I find more intimate and am really enjoying sharing with my new partner.
I guess this worries me because in the past I was very much a serial monogamist and I'm concerned about my own ability to make this all work. Is it just normal to have a transition period where you have to work to find equilibrium? I know I've read that relationships will naturally develop and transition, but can marriage interfere with this?