You both need to realize that being in the relationship is hurting both of you. There are always reasons that people stay in such relationships, I have no ideas what they are in your case, but the longer you stay together the harder it will be to separate. If you are mostly a secret though in her life, it shouldn’t be that hard. There has to be some feelings that you don’t feel wholly accepted by her, and if there is no future then there is no reason for her ever to reveal her love for you to others. It is only my opinion but I think that she is keeping you around for selfish reasons. Every one takes differently to this, but sometimes a relationship counselor can really help you. No matter what relationships aren’t easy, but if you believe that you would be better off without her then you need to do what has to be done and not put it off because of the thought of causing her pain. Often times one person or both people in a relationship really aren’t well together, but as soon as the mention of breaking up is brought up there is a sudden change that causes things to change if only temporarily, but it is often enough to put the talk to a stop. It is often just a strong emotional response and it can cause some internal discomfort, it is usually about the ego. To get broken up with can really hurt a persons pride and self confidence even if they know its not working. So one or both go on miserable and pretending to be a happy couple, if not to the world then to each other. Then repeats the cycle.