Mixed signals I think

met this girl in 7th grade. I really liked her and we became friends and the only time I ever asked her out the timing was just really off. I had just moved and we were then 15 and neither of us could drive to the other. Now we have gotten even closer to the point where she is one of my best friends and I am certain I love her. The feeling I get when I am with her is unlike anyone I’ve ever been with, friend or date. She has a boyfriend but there is so many signs that the relationship won’t be able to make it all the way. The biggest of those is he doesn’t make her feel wanted and he directly violates one of her dealbreakers. Over the last half a year we will be out with eachother til 4 am a lot, I’ve slept on same couch w her, sharin a pillow (when she had the option of a bed in a separate room, this was at her house), met her parents, and they said I’m the best guy her or her parents have brought around. When I started my ne graveyard job at a children’s med surg floor of a hospital , she stayed up until 5 to text me throughout most of my shift my first week. She’s talked about trips and moving in together and traveling together but she is still in her relationship of 2 years. I don’t know what to do because I cannot sacrifice the friendship but at the same time I want more. She is the only person I really hang out with rn because we will meet up to study together which is how I need to spend all my free time anyways