I am in a situation very similar to yours - but 10 years further down the road. My wife's drive diminsihed a dozen or so years into the marriage and then entirely disappeared 10 years ago. We average "sympathy sex" once or twice per year and really have no touching relationship throughout the year. I believe that the loss of libido was due to the onset of menopause, but who knows.
I believe that Jenoftheisland in her post on "why are we ld/nd" makes the point that there is no real reason why someone is nd - an interesting point of view but there must be reasons why one person is hd and one is nd - probably too complex with too many factors at play for us to understand at this point.
Anyway - you ask
"Besides not ML, does anyone else notice the negative impacts of a SSM? Do you notice yourself being short-tempered, resentful, and distant? Just wondering if I'm encountering "typical" emotional fall-out."
I can only tell you my experience of being in this situation for many years. My experience is only negative as you can expect. I was hoping that I could get to a philisophical place, rise above it and carry on without this part of my life. After all, I am told that having an intimate relationship is only a want, not a requirement to sustain your daily existence. In addition to discussing my feelings with my wife and trying marriage councelling (and yes applying the 5 love languages philosophy), I have tried busying myself with projects, fitness, hobbies etc. In my case, I have not found that I can not get to this "happy" place after 10 plus years of trying. I constantly feel depressed and unhappy by the absence of physical touch. I feel like I want to be alone now, even though I would be considered to be a people person.
The effect is very waring after many years. I now have taken to massage therapy (initially due to a sore back) in order to have some level of touch, even though it is nonsexual. I feel much happier after I have had some touch through this contact. I have often thought about having an affair, but I would feel horribly ashamed if this were to occur. I have also recently thought of having more than just a theapeutic massage in order to make up for the absence of sex life, but this seems ridiculous to me. And of course, what about divorse? These thoughts always are present but I know my wife loves me but just has no drive at all.
So where does that leave me - well as a middle aged and somewhat depressed male, conflicted by what to do and with no roadmap out. My advice - don't be like me, try and be more insistant on expressing your feelings to your wife and in return, don't expect to much from her. I am sure that she does not want to be ND but on the other hand you don't want to suffer the longer term unhappiness of this situation.
