Me (22F) and my partner (23NB) have been talking and encountered some problems.

Most of my experience in polyamory has been in pursuing romantic relationships. They have primarily sought out FWB and we started out as FWB.

We are planning to become nesting partners after I graduate college, and as such have been talking about how to handle pursuing new relationships. They have abandonment issues and anxious attachment, and are fearful of what could happen were I to start any new relationships. They are worried that I would no longer love/care about them as much if I got with a new person, and are scared at the prospect of no longer being my newest partner. I have one other partner who I'm a comet with and there have been no issues there, but I spend far less time with her proportionally and only occasionally get to see her. As such, there hasn't been significant jealousy on that front, but the prospect of me regularly going out with someone else, or staying over at someone else's place makes them worry and gives them jealousy and a FOMO. We've already agreed to close the relationship for the time being, both to keep from worrying them and to let me focus on my schoolwork. I want to keep this relationship strong and work well as partners, but I don't want to permanently close the relationship (and neither do they). As such, I was wondering how to handle that kind of jealousy, especially when its amplified by a fear of abandonment and an already anxious attachment style. They are reading this too, so we'd appreciate advice.