I’ll have a go at this.
Rousseau (who Voltaire outed publicly as scoundrel, but a brilliant one) spoke of the ‘social contract’ in politics. It has to do with giving over some degree of personal autonomy to the State to participate in the benefits of a civil society.
The US jurist Oliver Wendell-Holmes famously enunciated the Harm Principle - "your right to swing your fist ends where my nose begins."
Turning to marriage. It seems to me that you can’t bring everything to the relationship all at once. So commitment and both personal and corporate memory are needed by both parties, with some sharing and checking in about those understandings.
I think that need is undermined by avoidant traits (I’ve added that as an aside thinking of your wife’s situation InkHulk).
For example, I have just got back from a week away running a trial in another city. Got back last night. It’s part of what I need to do and how I support my family. I checked in every night with my wife. Obviously I could not be physically present but the commitment and promises hold things together just fine for a while even where you can’t be present. And I in turn am fortunate my wife wil pick up my share of the childcare and domestic tasks whilst I am gone.
Where there is that to and fro trust, and right now that is back again,I don’t feel jealous much. My wife can go away and do much as she likes if that is there. Where it is not present, it is like a line from the WB Yeats poem ‘Things fall apart; the centre cannot hold’.
Cheating, out of hand flirting, sketchiness in general, repeated selfish behaviour, cut at the heart of that virtuous circle. It breaks the social contract, even if that contract extends no further than our nuclear family. And jealousy is one of the consequences.
Bad or good ish at times, to a small degree, I think jealousy can mostly be avoided by prioritizing healthy respect.
Personally, I have no stomach for those who play with jealousy to stoke desire, or that kind of thing. It just comes off as tawdry to me.