Few thoughts from me, with the caveat that I haven’t been cheated on so cannot relate to that in particular.
At the start of my current relationship I would feel jealousy. I remember a particular instance where we were camping, and joined some other campers around a campfire. She was talking to another guy and I started to feel intense jealousy.
What was funny is that I heard the entire conversation and there was absolutely nothing about it that would sensibly make me jealous. There was no flirtation. The conversation itself was pretty boring, just the usual where are you from / what do you do. And the guy wasn’t particularly attractive either, which my partner confirmed later. Yet there the jealousy was anyway.
And what’s funny is I didn’t experience jealousy in another circumstance, of her going climbing one day with a male climbing partner, which it seems should trigger jealousy much more - one on one time, more attractive partner, shared interest, something fun/interesting to do, etc…
This was so clearly silly that I saw a great opportunity to eliminate jealousy, so I investigated. It didn’t take much, and I haven’t really experienced jealousy since, so this is one area I’d say I had it easy, but I think what it really comes down to is essentially allowing your partner to do whatever they want to do.
The realization was basically, look, I can’t control what she does. If she wants to cheat on me she will. And we will deal with that situation then. If she doesn’t then she won’t. It is out of my hands. So it’s better to simply recognize this and allow it instead of trying to resist or control something that is not possible to control.
At a broader level it’s like, I want an arrangement that is stable that both people are happy with. So I don’t want to control anything. Better to let it play out as it will, assert what I want, don’t assert when it doesn’t matter to me, and let it flow from there …