Hey I asked for help here before for my situation but by now I understand that jealousy does not ruin your relationship it's ubderlying issues. My partner recently met a person that became both her bestie and fwb and they're now having a blast together while our relationship is at it's lowest and very likely will not last. The bout of fights because I was jealous of the guy because my nees weren't met at all brought a deeper set of issues in my behavior that my partner struggled with for a while into focus. Now after some time that we spent separately while she was on a multi day eventcwith the fwb led to her feeling very distant from me. She is unsure of her feelings and retreats into herself because she anticipates that one of us will end the relationship soon and I tried everything but I am not coming through to her and now have to bide my time to see where we land. So no if your relationship isntact the jealousy will not fuck it up and despite nre your partner will not focus on the shiny new thing. It's because you somehow already fucked it up way before. So don't be like me and when your partner implores you to change ... change soon.