Oh this all sounds very hard and triggering. If I'm being honest. I also own that these feelings are real and I am letting myself have them. BUT part of me also is ready to label myself as "childish." I'm working on the self-love and the somatic approach to triggers, which is to LET THE EMOTIONS happen.
And truthfully, it is better every day. But some days are just not awesome and I don't love those days.
I'm sorry you feel triggered by that. It wasn't my intention. You asked how to feel more compersion and I gave advice on that. But you should know that not everyone feels compersion and that's okay.
Right now, you are working through emotions related to monogamy and monogamous programming. If you can start to untangle all of that, you'll have a much better experience. It's definitely very hard work indeed, and is only worth it if YOU want to be poly. If you are trying to white-knuckle through it so your husband can be poly, I've rarely seen that work. If monogamous is what you are at the core, then no amount of work will make this a happy relationship for you.
Based on other posts, I believe you want this too. You might want to get a poly-friendly counselor to really help you find that place where you can feel uncomfortable AND be okay with that, where working through feelings is uncomfortable, but no longer triggering.
For me, the hardest part is the activation of fight or flight in my body. When my body is freaking out, my mind goes along for the ride, and that ride goes downhill fast. I try to control my mind by recognizing what I feel in my body is my autonomic nervous system perceiving a threat. It's biology, not real. I have to recognize that feeling for what it is, and let my body recover from it without letting my mind convince me that the worst is happening. Once on the other side, I recognize that as true and am thankful I didn't let my mind convince me of all the bad stories it created while it was hijacked.
As you have repeated events that you work through, your body begins to learn that there is no threat, and that autonomic response starts to be less and less, until you no longer get it on a regular basis.
Now, for me, I'm only getting triggered when there is a change in regular behavior or patterns.