I want to share my own thoughts that rose up while reading Holmes as an aroace person!
Something in particular that resonated with me is Holmes's disdain for romantic attraction and love. Living, especially, in a world that does not acknowledge the a-spectrum, it is no surprise that any aro/ace person (even today) would feel alienated and misunderstood. For Holmes, this manifested as disgust and bitterness towards, in his eyes, the rest of the planet who seem to grasp it. Because of this isolation, it heightens Holmes's need to have himself understood. He lacks the language that we have today, and it only gets murkier with the then, and still vague and varying usages of the word "love".
It was not that he felt any emotion akin to love for Irene Adler. (SCAN)
This line has been interpreted to death, but with the belief that this is something Holmes had made very clear to Watson, it's him wishing under all circumstances for him to be seen as he is.
Living in a hetero-amatanormative world, gender plays a large role into Holmes's descriptions of men and women. Holmes struggles to admit that he finds women aesthetically attractive (especially early-canon), for example affirming that Irene Adler being "the daintiest thing under a bonnet on this planet", is only known to him according to the men on the Serpentine-Mews. However, he never heistates on commenting on a man's attractiveness. For example, Godfrey Norton, only a few short sentences later, is described by Holmes as "dark, handsome and dashing." Holmes feels no reluctance to describe men in such a way due to the fact that a Victorian culture would never mistake this for romantic interest.
We can assume that in the majority of cases, this is Holmes trying to clarify -- to not be seen as a romantic, which unfortunately then was understood to be equal with aesthetic attraction. It is very clear, however, that Holmes possesses one and not the other.
Later in the canon, he is seen showing open appreciation for women's beauty, not only in appearance but also character, such as Violet de Merville or Maud Bellamy. I speculate strongly that this came about from understanding love in a new way through his partnership with Watson, and finding that love comes in many forms, between any two people. Perhaps he no longer feels insecure about being seen as a romantic individual, because he has someone who truly understands him. I find that this is true on many levels for Holmes, not only on his lack of attractions, but also his eccentricities and deeper emotions, that were likely never properly understood by many.
It's always gotta make me tear up, huh? A huge aspect of H&W's relationship is accepting people as they are, so long as there is something worth valuing. They may be misogynistic, seem "positively inhuman" at times, or destroy their own body. But they may also just prefer a little solitude, communicate in a different way, or see the world differently.
