Leaving partner that did nothing wrong advice

I’ve been with my (22M) girlfriend (21F) for about a year and a half. For the longest time, she was everything to me — my day-to-day, my comfort, my best friend. But recently, especially after a vacation where we fought more than we connected, something in me changed.

I’ve started feeling disconnected. I don’t feel the same love I used to. I’ve even lost a lot of the attraction I once had. And the hardest part is, she didn’t do anything wrong. There’s no cheating, no major red flags — just this internal shift I can’t explain.

She cries often now, telling me how much she loves me and how much this is hurting her. And every time, it breaks me too. I feel like I’m hurting the person who would’ve given me the world… for what? Just because something feels off on my end?

I keep wondering if I’m just going through a phase. Maybe all long-term relationships hit a point where things stop feeling shiny and new. Or maybe I really am falling out of love and I’m dragging this out because I don’t want to hurt her — or face the guilt of leaving someone who still loves me so deeply. She was such a place of comfort for me every time there was an unbalance in my life she was there and it’s all going to be gone.

It feels like I’m shooting myself in the foot. I miss the way things were, but I can’t seem to fake it anymore. I don’t know what the right thing to do is. Has anyone else felt this way and come out the other side — either by rebuilding or letting go?

TL;DR:
Been with my girlfriend for 1.5 years. She’s loving, loyal, and hasn’t done anything wrong — but I’ve been falling out of love and losing attraction. After constant fighting on a recent trip, something shifted in me emotionally. Now I’m torn between staying in something that doesn’t feel right or leaving someone who still sees me as her everything. I don’t know if this is just a phase or if I’m making a huge mistake.