In a poly I would guess people need to feel attached to a group not a single individual, in a sense loving all people in the group almost equally. Mostly, we are not raised that way and culturally it would be unconventional, to say the least.

These are good insights, but I meant how do you adress it within the concept of a non monogamous society.

All good points, but this doesnt really answer my question. If we imagine this hypothetical non-monogamous society, with no social constructs incentivizing monogamy, jealousy being in human nature would remain a driver towards monogamy. I imagine historically this is how most religions arrived at propagating monogamy. In christianity and judaism for both genders, or in islam for female monogamy, as jealousy was such a common driver of conflict that may even escalate into wars. Enforcing monogamy as the moral choice has some merit, if it avoids bloodshed, though obviously ideally people capable of being in non-monogamous relationships shouldnt be punished for being in one.

People who do not depend on relationships simply don't enter into relationships.

For everybody else, there is the normal and perfectly human feelings of jealousy, attachment, fear or loss, and feeling associated with self-confidence.