I agree with 38rakia38, unnaturally dissolving the relationship will simply leave a guy who feels guilty and still retaining feelings for his ex-girlfriend. Not that you suggested you were going to persue that course.
I would suggest that you are being unnecessarily unfair on yourself. Firstly, as a doctor I would be inclined to believe she is intelligent, but this does not mean that you are not. Intelligence presents itself in many forms, and I have met many apparently 'unintelligent' individuals who have intellectually impressed me far more than the apparent 'intelligent' aerospace engineering students I have studied with.
I think the first step you must take is recognising your own worth. In my experience everyone has their advantages and disadvantages, and the more someone focuses on the career, the more they are lacking in personality and interest in others, especially their partner. You should perform a self-examination and determine what are your strengths and weakness, knowing yourself will bring confidence.
Additionally, I am inclined to encourage you to either patiently and without intruding in their relationship, wait for this possible break-up, or perhaps seek out someone who is more available.
I know what it is like to want someone you cannot have, I once had a relationship with a married women, and it damaged her life and my relationship with her husband, who after meeting him; we had become close friends. I thought love would prevail. It did not. This has not scarred me but it always reminds me, that it is not our place to involve ourselves in the relationships of others, not matter how much we want someone. I am sure there are many people who will love you, they may not be who you think you want, but if you look hard enough, I am sure you will find that some of them, you do.