I'm more in your husband's position than yours (I'm the pivot of a primary vee, and one partner is newer to poly and less comfortable with it). That said, I'm happy to share some of the strategies we've been using to work towards compersion and feeling okay with our constellation of people:
~ We do our best to ask if it's a good time to discuss relationship stuff (whether it's NRE-style gushing or concerns or a boundary discussion or whatever) before starting to talk about it.
~ If I'm contemplating setting up a date, especially with one of my secondary/tertiary loves, I check in with Twig beforehand: what percentage is he at emotionally? (We found putting a number to it really helped us talk.) If he's feeling really stressed and not up for handling it, I'm more likely to postpone. (The deal is that he has to tell me how he's doing, and I have to make an intelligent decision about how to act-- I do NOT have to cancel.)
~ If Twig's feeling uncomfortable about a situation, we talk about little rules we can make that would make him feel better and that I'd be completely okay with. (Twig and I are monogamous shower buddies, for example, and it sounds from your posts like some kind of texting rule might really help you, KT.)
~ We say it on here all the time, but it's worth repeating: communicate, communicate, communicate! Little miscommunications can get ugly quickly, as you know, and the more you talk (both about plans and feelings) the more information you all have to make good decisions.
Keep posting and sharing-- we're here for you!