I'm assuming that Cherry is also around your age? 19 or so?
If that's the case, I would advise you to remember that she is YOUNG. Dating, relationships, and sex might all be pretty new to her in general. When you're young, you're often insecure about dating, sex, and relationships (without even realizing you are insecure) simply because it's all new and confusing.
You're young too, but you have the benefit of having questioned society's norms about relationships and figured out what you want for yourself.
I had a relationship with a poly guy when I was 21. I was mono (at that time) and he was poly. Before, I had never considered that there were any other options besides being monogamous. I liked the idea of an alternative type of relationship and I wanted my boyfriend (Techie) to be able to be himself.
But I was also not interested in dating anyone other than Techie, and I was uncomfortable with many of the things he did. I understood that he and I had very different perspectives on relationships, but I believed that we could be happy meeting halfway on some common ground.
He basically refused to meet me halfway and kept insisting that he could not be bound by any rules or restrictions. He also refused to explain what exactly he wanted (with his relationship with me or with anyone else) and insisted that he get to do whatever he wanted because "love has no boundaries."
It was hurtful and insensitive to me. It was also very frustrating because I was very introspective and self-aware, and I knew that most of my issues were due to my insecurities and inexperience. (I was a VERY late bloomer and Techie was my first sex partner, although I'd had one boyfriend before that. But I'd never even flirted with anyone else, ever!)
I explained repeatedly about how insecure I was, and how I was trying to overcome it, but Techie really did nothing to make me feel secure with him.
The idea of non-monogamy appealed to me, but I felt like I wasn't quite ready for it yet (and told him so). I explained to him repeatedly that because sex was so new to me, the idea of him having more and more partners freaked me out. But he did not care at all, sulked whenever I told him his behavior hurt me, and threatened to break up with me constantly.
Also, he did nothing to show that he cared about me. Actually, he treated me like crap. Which should have been obvious to me when I was with him, but wasn't (because I was YOUNG).
However, in retrospect, some of the things Techie wanted to do, which bothered me then, I now think are reasonable and would no longer bother me at all. I was so insecure with myself I really couldn't handle an open-type relationship, even though I wanted to.
What frustrated me most about Techie was that I offered him many middle grounds, and it was never enough for him.
When I supported his relationship with his live-in sort-of-ex girlfriend, it wasn't enough--I had to want to hang out with her constantly. When I encouraged him to continue to visit friends in other cities that were sometimes friends-with-benefits, it wasn't enough--he demanded I go with him to meet these friends, and he sulked for days when I said I wasn't comfortable with that. When I suggested he have certain days of the week or certain weekends where he went off to meet other girls, it wasn't enough--he needed to be able to flirt with every girl we ran into while walking across campus together.
When I talked to him honestly and openly about my jealousy and how I wanted to work through it, he accused me of being crazy and said we had nothing in common if I didn't understand "infinite love."
So I guess my advice is--if you want to be with Cherry, actually listen to her and try to understand her, and respect her boundaries. You present her as being really close-minded about poly, but maybe you aren't really listening to her.
You don't get to just do whatever you want on the excuse that your nature is poly.
And if you do decide to continue a relationship with her, for heaven's sake don't blame her for making you miserable when you finally do end it.
Single, straight, female, solo, non-monogamous.