It doesnt sound like she is "happy" with you either, so it begs the question, why is she still in the relationship? Obviously its very easy to comment without any emotional involvement and only hearing one side of the story, but, just about every relationship exceeds its lifespan and will drag on way past its sell by date. No time is a good time but I cant believe either of you doesnt know the end is coming, so doubt it will be a shock to her, get it done and both find what you want in life, which obviously isnt each other.