Hi,
Personally, I do not think there is nothing wrong with you for thinking you may want something more. It doesn’t necessarily mean you do not appreciate your loved one. It sounds more like you just aren’t ready to settle and feel you need to experience the world a bit more, including other women and relationships. You are 27 years old, there is nothing wrong with that. At the end of the day, do what you think is really going to make you happy. Do not fear what other people will think because you took the road less traveled. When its the one, you just know…
Follow your gut and don’t look back.
Good luck.