1) Why do you want to turn your smoke alarm off? That doesn't solve the fire in the house.
Basically, I need to know where to begin with coping with this jealousy. I don't want to become so jealous that I push him away.
Jealousy is a flag emotion. It is neither wonderful nor horrible. It is an emotion alarm flag of "Hey! Look deeper in here. Something is not right."
What needs are going unmet? Needs he is not meeting to help care for your buckets as your partner person? Are you being disregarded somehow by him?
What needs are you not meeting yourself to care for your own buckets as your main bucket tender? The buckets of mental health, emotional health, physical health, spiritual health? Are you disregarding your own needs somewhere? Compromising yourself?
2) If you do NOT want to be in a polyamorous relationship structure, say so. Why are you agreeing to be in one at your own expense?
Everyone has the right to pick what relationship model makes them happiest. You are NOT WRONG to want a monogamous relationship structure for yourself because that model brings you the most mental and emotional peace and happiness. You deserve to be happy. You might not LOVE it if it turns out he wants a different model for his life. But it is HONEST at least, and nobody is compromising themselves unfairly.
I had my objections, but for him I agreed to it.
3) Why do your run your relationship with him from a fear based and/or passive position?
Why are you considering yourself "less than" anyone? Why do your override your OWN LIMITS for him? If you habitually treat YOURSELF and your wants/needs/limits as "less than" how can you feel anything but "less than?" And if you end up in emotionally unsafe places because you do not listen to your own limits, then who is to blame? Please YOURSELF first. Being assertive is not being selfish. Everyone has limits.
Why do you not exercise your right to determine your relationship fate/destiny/life for yourself? You want what you want. That is your limit for relationship model(s) that make you happiest. Go for them, so you can BE at your happiest.
You know you can choose to have a conversation with your partner to determine where you stand together as a couple, right? Where YOUR wants, needs, and limits are heard. Where his wants, needs, limits are heard. And if things do not line up, they do not line up. Unfortunate, but not the end of the world. What's the fear behind not wanting to "push him away" speaking to? Would you rather be partnered badly/not matching well than alone?
No judgement here -- just some food for thought to help you think things out for yourself and get to the bottom of the matter. Personal introspection/growth is sometimes very challenging.
has a huge section on jealousy -- but if the starting gate issue is "No, polyamorous relationships are not something I want for myself and it just does not float my boat" you can solve the whole shebang by being firmer on what YOU want and seek in your relationships. YOU HAVE THAT RIGHT, and there isn't anything wrong with wanting a monogamous closed relationship model. You break up clean, and when ready you date anew and try to seek someone who matches you dance card better for your wants/needs in relationship.
All that isn't easy to FEEL.
But it's pretty straightforward to THINK out. It is what it is. Listen to your Jealousy Alarm trying to tell you something. Sort out what it is buzzing for.
Hope this helps,