Is limerence about someone that's already in a relationship worse than someone that's single?

I'm basing this question off my own experience. Long before I even knew there was even a word for long-term obsession over a single person, I had my own experience with limerence starting in my freshman year of high school (yes I'm serious, but stick with me here). I met someone, or rather a social group, when I was part of my school's theater program. There was this one person I had seen around campus but never really knew anything about her (she was a senior at that time). After a bit of time hanging around her and her friend group, I saw my LO holding hands with another guy. I asked one of her friends if she and this guy were together, to which he said they were. I wasn't entirely surprised because she was one of the most attractive people I'd seen, along with most of my crushes being taken in general. Her friend did also mention that there were a lot of guys that were going after my LO too, so there's that. It was made more confusing to me whenever I saw them holding hands or cuddling, not once did I see them kiss. As someone on the spectrum, I never really understood at the time that those little public displays of affection could be more than just short term things; I thought of kissing as what ties the knot for whether two people are together, but I digress. I ended up spontaneously telling my LO I liked her after I saw another crush of mine being asked to the prom by her (the other crush) boyfriend in front of everyone working on the theater set. In hindsight, I think it was what made the limerence far worse than it should've been, knowing that (1), my LO was a senior while I was a freshman, and (2), she was in a relationship. I spontaneously hugged her after we both said goodbye on the last day of school before she graduated. My obsession with her grew more and more that summer and never heard much about her. She didn't have any social media, and I didn't really hang around her friends outside of school. My whole image of her turned into the idea of her, a 17 year-old girl with pink hair similar to Ramona Flowers. The fact I wouldn't have able to be with my LO with those two things in mind further intensified the feeling. There was no closure, and my obsession grew and grew over the months, reaching its height around the one year mark of when she graduated. I switched schools after my sophomore year in due part to that. It probably took me until the second semester of junior year before I moved on. I eventually got closure a few years ago when we were both at a bonfire a friend invited me to. We interacted in the same friend group, and the last thing she said was "Nice meeting you". You might think it would've broken me, but ironically, it didn't. It was a reminder that I've changed dramatically since then, and that limerence isn't something that lasts forever, whether it's in adolescence or adulthood. Since then, I've come to wonder something I never really thought about until recently, which is whether limerence can become more intense when the LO is in an existing relationship. Just knowing there wouldn't have been some foundation for dating and/or mutual attraction to begin with, regardless of if you asked them out. Maybe this is just me being semi-cynical because I live in a small town with a horrible dating scene and a limited pool of people to date that leads me to assume most people are taken. But in general, could these circumstances make limerence worse? I'd like to get somewhat decent input on this because I haven't really known other people that have had a limerent experience.