You are not a git, and honesty IS the best policy, as long as it's said in the right way. First, though, do you love her? I mean, can you imagine life without her? Do you really want to say goodbye? Or do you merely pity her? You must be clear in your own mind and get your life and future sorted out. Suggest 'interesting' sex to her, such as role-playing and fetishes, that can be fun. But if she won't indulge, then say to her (not in a bitter way but in a hurt, disappointed tone) 'Well, to be honest I don't find our lovemaking very exciting any more' or even 'I find myself less attracted to you'. Maybe then she'll do something about it. Good luck.