Some people who are poly also have anxiety. It doesn't mean we shouldn't be poly.

Some might think that those of us with anxiety shouldn't be poly. If one relationship makes me anxious, wouldn't multiple relationships make me more anxious?

I used to be in a monogamous relationship. I worried a lot about that relationship. I used to worry that  that person wasn't the one I "should" be with, and wonder whether I ought to break up with them. Was I holding them back from dating someone better suited? Was I holding me back from dating someone I'd be better suited to? In the end, that person dumped me and it sucked a lot. The anxiety I had after the breakup was probably more ongoing than the episodes I had during the relationship, but not any worse.

These days I am dating someone I'm much better suited to. I met him after I had researched and decided to try polyamory. Like many others, I define this as the practice or desire to have romantic and often sexual connections with more than one person at a time.

Obviously, this means I'm not holding anyone back from being with other folks, and I'm not held back from being with other folks either, except that obviously I don't date the monogamous now. On the other hand, it gives me a whole other set of things to worry about -- will my partner like someone else better? Leave me for someone else? Am I comfortable not being the only person in their thoughts?

Logically these things don't make sense to worry about.

1. My partner could like someone else better whether or not we are monogamous. It's shitty to compare people, so if they are doing that or at least not striving against it, they are not a good person for me to date.
2. My partner could leave me for someone else whether or not we are monogamous. See above.
3. No one is ever the only person in someone's thoughts. Even if you are monogamous, you still have parents, friends, children, pets, co-workers, etc. People who are jealous of all their partners' other relationships are abusive assholes. So if my partner cares about all those other people, and also other partners with whom they probably also have sex, there's no reason to worry about that either.