Can you love your partners in different ways? For one person, I feel red, it's deep, intense, passionate. For the other, I feel pink, it's giddy, sweet, delightful. I don't feel as though one is lesser than the other. I'm not dating either one of these individuals but I am "involved" with both them, (and completely open and honest about it with both parties). I'm in love with both of these people and I don't know if this means I'm poly or if I'm in some gross love triangle. How do I know?
If everyone is happy and healthy, then there is nothing “gross” about this. If everyone involved is okay with the arrangement, if everyone is getting all of what they need and most of what they want, then you’re fine. That’s how you’ll know - by checking in and making sure things are okay, and keeping those lines of communication open. That’s it! I know it feels kind of tautological, but if it’s working, it’s working. There’s no standard of healthy relationships you have to measure yours against to make sure.
And to answer your other question - of course people love their partners in different ways! That’s incredibly common and normal and just a part of human experience not limited to polyamory or sexual/romantic love. Take friendships, for instance! There are some people I can just sit on my couch with and chat for hours; there are some people who are the life of the party and keep me cracking up but are less likely to have that cozy intimate evening with me; there are some people who are insightful or funny in group chats but probably won’t ever be my bff. And that’s okay! All relationships are different and it’s wonderful that you have some language and metaphors to help you honor and cultivate them on their own terms. Here is a lovely video readaloud of a book called Love You The Purplest that uses similar imagery to talk about a mother’s different loves for her two sons.
The only time it would be an issue is if one of your partners feels left out or slighted by the differences. If you’re always planning exciting new adventures with one person, or leaving cutesy romantic notes around for one person, but the other person doesn’t inspire that kind of energy in you, the person who isn’t getting that kind of affection may not be okay with that arrangement. Or, they may be totally fine with it, because you two relate to each other in different ways that work for you two! Don’t make assumptions or fall into vague anxiety - some people really don’t care about cutesy notes, and you don’t have to have completely identical relationships with everyone in your life. Just check in and make sure everyone’s happy and healthy, and then keep doing you!