My (26M) girlfriend (25F) and I have been together for over 6 years, but I feel like she has lost interest in me over time

I (26M) met my girlfriend (25F) 7 years ago while we were in college and swiftly developed a crush on her. We got together not long after, which eventually led to the best couple years I’ve ever experienced in my life. We were deeply in love with one another, and we couldn’t imagine our lives without each other. It didn’t take long for her to move in with me, and we spent a lot of time with one another doing things we both enjoyed doing (e.g. watching movies & shows, playing games, etc.). The sex life was also great—though we didn’t actually have sex at the time (she wasn’t ready and I didn’t want to pressure her to do something she wasn’t comfortable with), we did literally everything else and it was enough for me then. Another important detail worth noting is that I grew up far away from where we currently lived—I’ve always told her that in the long run, I wanted to move back to my home country (for a number of familial reasons I won’t get into), but she had always expressed that she was open to the possibility of moving back with me. I’ve even taken her to my home country a couple times where she met my family, explored the area, and concluded that she would be happy to move there in several years’ time.
But that was several years ago. Now, many things have changed. First and foremost, she’s much less open to the idea of moving back to my home country, and she would rather stay where we currently are (which, for context, is the city where she was born and raised). Second of all, remember the healthy sex life I mentioned earlier? We haven’t made much progress from that. In fact, I would say we’ve regressed significantly. Not only are we still virgins, it appears as though she has lost all sexual attraction in me. We no longer do the things we used to do, to the point where we barely kiss and cuddle anymore (things she used to love doing). In addition to that, I also feel as if she has gradually lost her emotional interest in me as well. The love feels increasingly one-sided, which has gotten much worse recently as I have noticed her reluctance to even say “I love you too”. At the moment, our relationship resembles that of roommates far more than it does an actual long-term romantic relationship.
Though this is something I have noticed for quite some time, we’ve only had that conversation recently when I brought it up to her. I told her that I felt like she has lost interest me, which she neither confirmed nor denied. I asked her if she still loved me, to which she mentioned that she wasn’t sure. I asked her if I did or said anything wrong (and apologized in advance in case this was the issue), to which she responded that I didn’t need to apologize because I haven’t done anything wrong. I asked her if there was anything I can do to “fix” this, to which she said she doesn’t know what I could do. And after this conversation, I’ve noticed she has become increasingly distant to me.
I don’t know what I should do right now, and I’m in agony. Is our relationship doomed to fail? It’s incredibly difficult for me to come to terms with that possibility, as this is a girl that I wanted (and still want) to spend the rest of my life with. This is a girl I wanted to marry, and with whom I wanted to have a family and grow old with. Yet day by day, it seems as though that dream is slipping and I have no what idea what (if anything) I can do on my side to earn her love back and return our relationship to what it had previously been.
Any advice would be greatly appreciated, thank you.
TLDR: I’ve been dating my girlfriend for over 6 years, and I feel as though she has lost interest in me (physically and emotionally) over the last few years. I brought it up to her recently, and she mentioned that I didn’t do anything wrong, but she wasn’t sure if she still loves me or what I could do to “fix” this.