As that’s assuming every partner gets the same amount of attention as in a mono relationship, but your partner(s) has other partners, they can hang out with someone else when you are busy or need some time for yourself. How much time you spend with your partner(s) is very flexible.
In fact, in my polycule, people tend to actually get more alone time, because you are not the sole person fulfilling your partner’s romantic needs. It’s remarkably flexible, and, while it may need some planning and/or making sure you tend to your relationships, in my case it feels remarkably straightforward and freeing.
It’s a thing I like a lot, actually. Not feeling like I am the sole person responsible for someone’s romantic needs. It lifts a fair amount of stress off of me.
This flexibility means you can tune a lot of things, into what works for everyone.