Is it okay to be polyamorous with a preference for monogamous relationships?
I'm going to do that annoying thing where I sort of reject the entire premise of the question, and then answer it anyway.
You don't need to ask me whether something about who you are or what you prefer is okay! I'm just some blogger - and there's no almighty arbiter of whether a way of being in relationships or a certain identity is "okay." You do you, in whatever way is healthy and honest for you and your partners.
But since you asked - of course it's okay! Plenty of people fall under the umbrella of "could be happy with A or B, but generally prefers A." Plenty of people could be happy and fulfilled in a polyamorous or a monogamous relationship.
If you want to identify as a polyamorous person, that's fine! You could also identify as polyflexible, monoflexible, monopoly, poly-mono, monogamish, or whatever other term feels right to you. But if you have a preference for monogamous relationships, it might make more sense to actively seek out monogamous relationships instead. The good news is that the majority of people identify as monogamous (whether because of something innate or socialized assumptions), so your preference should be relatively easy to indulge.