She says she has fallen out of love...

I am in a long-term relationship with a girl who claims to have fallen out of love with me. She says we have slipped into a kind of familiarity that makes it difficult for her to see a future together. I don’t know what she means because I thought all couples longed for this kind of sense of comfort. I have tried speaking to her about what she would like to change, but she doesn’t know either. I have asked her to consider going on a holiday with me so we can discuss this and find a solution, but that doesn’t appeal to her. I want to save this relationship because I believe we are good together but can’t do anything if she doesn’t want to work with me on saving it. Should I suggest taking a break and getting back after a few months? Maybe a few months away from each other may change how we see this.
Time off is a good idea but doesn’t address the heart of the problem. If your girlfriend doesn’t like the idea of familiarity, it’s obvious that the two of you need to change how you interact with each other. This isn’t an insurmountable issue but will undeniably require you both to pull together. If she isn’t amenable to having that conversation and doesn’t have an idea about what can be done to make things better, it may make sense to reach out to a professional and consider counselling. However, that is an option only if she wants to save this relationship as much as you do. I would try and have that conversation first.

My friend and I are in love with the same person and don’t know how to resolve this. It is leading to a lot of friction which is sad because we have been friends for a long time. How do we manage this situation?
It seems as if the person you are both in love with has no say whatsoever. You should both consider that.