Wow, what an opening! It sounds like you have experienced many things both in monogamy and non-monogamy.
If you and SM are both chafing over your current boundaries, then yeah I think it's a good idea to renegotiate them.
Rebuilding trust can probably be helped along by increasing the quantity and quality of communication that you and SM do with each other. You have to let him know when you are feeling insecure and need an extra text, favor, hug, night out together, whatever it is you need.
I went right from monogamous to poly but learned many things the hard way along the way. I guess most people have a rough go of it when they're just trying poly for the first time.
Thanks for starting this blog, I'll keep an eye on it.
Love means never having to say, "Put down that meat cleaver!"