Yes, you are starting to see her for (and accept) what she is and not for what you would like her to be. Often we want someone because their presence in our lives feels like the missing piece in the puzzle: our life. Have you ever tried to plan your life and life shows you that you do not have all that much control? This is because life is not a puzzle. It can just be puzzling to understand, sometimes.
In nature, all things fall in the perfect place when the conditions are right. In fact, nature isn't puzzling because it always looks for the easiest outcome. Electricity will always take the easiest route. In chemistry, molecules come together because it is the easiest way to achieve equilibria and/or stability. In biology, the plant will grow towards the sunlight, etc. These are natural laws and all you can do it accept them.
In England, we say "the proof is in the pudding." Is it easy for you to be with this girl? Yes. Is it easy for her to be with you (or perhaps anyone)? No. There is no puzzle. This is the natural outcome of the situation. It is far easier to go with it than against it (though you cannot say that you have not tried). Trying to cause an artificial solution in the natural domain is going to backfire and be unsuccessful. I am under the impression that you are here.
Nevertheless, you feel that you have found in this girl the missing piece to the puzzle. But, in truth, nobody can complete you (or incomplete you). You are born complete and all the answers that you seek, for happiness and liberation, are within you. It would be a mistake, an unnatural thing to do, to look for answers in somebody else. One of the pop reasons for this is because they will always be the most important thing to themselves. Fundamentally, they have a different focus on what is important at present. And, fundamentally, in such a situation, make no mistake, you will come second. Also, if you love them, it would be selfish to impose on their personal and natural growth/direction/life path priority. That is why a part of love is in the letting go. Another pop reason is that you should not give someone else the keys to your happiness. This is what you are doing. Irrespective of who the person is, it is wrong. It will not work. You have to find the answers that you seek, within. Find completion, in the growth through that. And then find someone who will compliment you. And who you will complement. Like Yin and Yang. Conversely, by looking to someone to complete you, you are implicitly a dependent (incomplete) party in the relationship from the get go.
If letting go is difficult, then I would suggest that perhaps this is not real love. Love is love irrespective of the form it takes. If you an an animal lover and you have an animal that you love which would fare better in its natural habitat, than at home with you, out of love, you would release than animal. So, if this is not real love, it is a plaster for something. What is this situation a plaster for?
Well, if you are inclined to give someone else the keys to your happiness, or hold the (undue) belief that they will complete you, this in and of itself suggests that you feel an inadequate driver. And there is a reason. At face value, it is puzzling why if you feel inadequate, as I explain (why), you should want to give the keys, to happiness, an emotion, to a person who is emotionally unavailable, and therefore inadequate themselves.
You want an emotionally unavailbale woman to love you and be with you. You are looking for love - yes - in a place where there is no love. What does this tell us? To answer this question, a quote that springs to mind is from an astrology book by Linda Goodman, "'When Good is hungry, it seeks food, even in dark caves, and when it thirsts, it drinks even in dead waters.' A perfect description of Scorpio." I can see the root of this isnt about being hungry for sex or physical desire. The root is that you are thirsty for love. You then choose the woman who you know cannot give it. Why? Because on some level you feel unworthy of love. Face that. Then face the fact that you are love and you are loved and that you are loveable. You are loved by a far greater force: the universe. This is not mumbo jumbo philosophy because to receive (perceive) that love, you need to know what real love is, in order to be able to recognise it, keep it and cultivate it. The truth is, this situation in which you find yourself, right now, is the universe's way of loving you. And one day, once you are at peace with truth (i.e., accepting of the limitations of other people), you will know true love in your life. It is the only love worth having and it is the only way to stop this train to nowhere.
To deal with it in a different way, by hanging on to this person, what is it going to solve? It may seem to you like it will solve something important, but the universe is showing you that this is not the solution. You are amazing. You deserve more. You know this, you just have a problem accepting it.
Cultivate love in youself. It will take time. A good way to do this is through giving to others who are really in need. The universe gives us not always what we want, but always what we need. what you need is not in her. It is in you. As much as it might feel daunting (your word) to explore this. There is no escaping it. You shouldn't feel drained (your word) doing it. Often draining is a feeling that comes when you are actively preventing yourself from using the situation for its purpose, or misusing it.
Dont be afraid to let go, it is empowering. I am not a psychic so I cannot tell you what the future holds, but I know that it will be far easier if you accept people for what they are, respect unconditionally the journey they are on, as a universal manifestation, and focus on cultivating love within yourself. If you dont know how, pray for it. It is why I say "dare to do it" because it is the only way to get to where you want to be ultimately. This is your death card (in tarot). It is time to take steps and walk through that door (that you know is there).
I am going away for two weeks. I'll have no internet, so will be unable to respond to messages. Best wishes for your journey.