Am I being superficial?

TLDR; been with girlfriend for 6 years. Stopped having sex, and now have lost attraction. I've been mulling it over for 6 months, going to therapy, really don't know what to do. feeling tired and seeking advice.

My girlfriend and I (27F, 25F) have been together for 6 years now. Our relationship has been great in many ways - she brings me so much happiness, laughter and fulfilment in lots of areas of life. She is my best friend!! More than that, she is my family. It’s hard to imagine life without her.

The thing is, I keep getting this gut feeling that maybe we’re not meant for each other. I’ve been going to therapy for around a year now to try to work through this, and work on myself too, as I don’t want to do something I’ll regret. Although I’ve processed and learnt a lot about myself, I still don’t know how I feel about this relationship.

I think this “gut feeling” started maybe 2/3 years ago, which kind of coincided with when we stopped having sex often. We’ve had sex maybe a few times these past few years. I’ve tried to initiate, but she’d reject my advances because she was tired/not feeling it. Completely valid, but I stopped initiating eventually because I didn’t feel that wanted. Now we haven’t had sex for almost a year I think? It’s been so long that i honestly, sadly, don’t feel attracted to her in that way anymore.

Around 6 months ago, I had a honest and open conversation with her, about what she thought could be improved in our relationship and also what she thought we could do to improve our (lack of) sex life. She said she would like more intentional time / more compliments. On my side, I thought everything was good except passion / sex life.

We’ve been working on these things for 6 months now. I’ve been working on this and trying to plan more dates, notice little things more, but now I just don’t want to have sex anymore. still love her like crazy, she’s my person, but I don’t want to kiss or have sex with her… it breaks my heart and I don’t know what to do / say.

Has anyone been through this before? Loving someone but having no attraction? And also with a gut feeling that we shouldn’t be together? It’s honestly so confusing because there’s so much love there. I don’t want to make a decision I’ll end up regretting. But equally I feel so stuck, I'm at a crossroads, like I’ve been thinking about this for so long and nothings improved. I'm so tired. I’m scared that if I break up with her, it’ll haunt me forever. What if I look back when I’m older and realise all the good things I’ve lost? Sorry if none of this makes sense, I just wrote this all in one go.