Some context:

I have a friend, let's call her "Marie," who I met during my undergrad. Through the course of school, we became very close-she shared a lot of disturbing things with her past, and we became mutual confidantes. Some would've called our relationship slightly codependent. We share many of the same interests, and we generally and genuinely have a great time whenever we're hanging together.

One time, in 2016, I asked her if we could try dating. She considered me a brother, and wasn't interested in pursuing anything further than that. As much as it hurt, I still bent over backwards to keep her in my life. I would often pretend things were awesome and not let on that I was (and in some ways still am) head-over-heels for her. In my mind, she's the perfect partner for me. She's basically "the one that got away." Fast forward to today, our hang average is low, but we still keep in occasional contact. Every so often, we hang out, listen to music, and it feels just like it did in school-so much happiness for me, and her. We often say "I love you," as family would-not in a romantic way.

To the point of the question: I'm well aware that it's not a possibility for us to get closer than we are now. She almost never instigates times to hang out or chat, and I often worry that I'll come off as needy, or obsessive. She's aware of my cognitive differences. I feel sad because, partially, I still remember the feeling of being eight years younger, and madly in love with her. Additionally, I want so badly to bring up how I feel like she isn't always pulling her weight in the friendship. She's an INCREDIBLY busy person, and sometimes I wonder if she has some undiagnosed ADHD or other neurodivergence. But, I don't want to possibly sour the friendship. She has said that she regrets that we can't hang out as much as we ought to. Part of me also wants to cut ties, and 'set her free,' but I know that would only bring sadness for both of us. We both enjoy having each other in our lives, and I usually am able to carry on fine.

*TL;DR*: I have a friend who, in spite of our attitudes towards each other, isn't able to fill the emotional hole that a true best friend ought to fill, at least in my mind. Am I just obsessive?