I'm not exactly new to polyamory. I've been studying polyamory for years, reading, lurking here, listening to podcasts, etc, so I'm very familiar with poly concepts and terms. And I have been polyamorous for over a year now but haven't gone out with anyone for more than a few dates before cutting things off. But I've been seeing this new guy and it seems like it might develop into more of boyfriend/girlfriend situation. I'm in the throes of a massive crush, experiencing NRE, and am positively drowning in limerence, which all seems to be about right. But there's one element of my relationship with this guy that is really making my anxiety skyrocket.

He's new to polyamory, which already made me feel a bit hesitant at first, but he's also in the process of establishing another relationship with someone else, and their relationship is moving much quicker than ours. Usually I'm not concerned about dating people who are already partnered. I've done it a few times, even though the relationships didn't last, and I didn't experience jealousy or worry around it. But I feel like establishing two new relationships is a different beast entirely. I know that I wouldn't have the emotional bandwidth to do so, even just one is a big lift emotionally. I understand that not everyone experiences this stuff the same way, but I'm getting the general feeling that he just doesn't feel that strongly for me. That my spot could have been filled by any other person and it wouldn't have mattered. And the idea that maybe he's experiencing stronger feelings for a different person during this phase of our relationship makes me feel sad.

I have sometimes felt like much of my dating experience, especially dating men, has been slipping into a place in their life that they are looking to fill, rather than a process of becoming special to someone. People are more often interested in what I can do for them rather than me as a person. So with this situation, I'm finding myself extra worried about being seen as disposable or as a placeholder.

Do other people have opinions or experience with dating someone who is simultaneously establishing relationships both with you and another person? Any thoughts about the situation?