Defining relationships within the lens of Polyamory

Newish to polyamory, but not new to the concept and conversations around it, and I think that is what I am looking for here. Partnered for several years with one individual, we are both poly, they have 2 other partners and I have a someone else I've started seeing.

I have always loved harder/more than those around me. My longest relationship has had it's ups and downs, and not comparing the individual I'm talking to, but comparing the feelings. And it feels different than NRE. All of my relationships have felt "different" than traditional relationships. Heck, even my BFF in high school, I always thought I had the hugest crush on them. We did everything together, random day trips, went out to dinners and took turns paying, everyone thought we were already together. And I thought that was what I wanted. Never told them how I felt, I did not date in high school but always was the one that hung out with everyone.

We are still friends, hang out together, they is def not poly and different beliefs than me. Sure, fine. But I always wonder if my (grading scale for lack of better words) is off. Is that just how friendships are supposed to be? And my scale has just been wrong all along? I have a friend now I could see it going the same way. I have feelings for them, think about them all the time. But how do I know if it's meant to be just friends, or if It really could be something? And how does that work into my current partnerships? Because it does feel like a partnership, not just a friend or NRE or anything temporary/

I have been doing a lot of work around validating non-sexual relationships. But what is a sexual relationship? The more I read, the more I see friends who can have sex casually. I see romantic relationships between friends without having sex. Heck I see romantic friendships that are more romantic than I've had with sexual partners. And lines get confusing for me seeing all of that, is there an established code I just have not come across?

Okay you've made it this far, I'd like to hear how you have navigated similar relationships like these in the past, and curious on how you define and label the relationships in your life and how they came to be, especially within the lens of Polyamory. This feels different than just non-monogomy, I truly feel like I love and am deeply invested in these individuals, and growing our relationships, no matter what they look like.