Thema: Seems like Alexithymia gets worse

I used to join all the clubs, participate, blah blah blah.

Now I find I don't like to be around people.

Over the years I've developed more and more ways to blend in, and now I have no desire too.

I know that I love my kids but its more a understanding of fact than an emotional response.

BINGO! You aren't really "feeling" love, per se. You are "manufacturing" what you think you are supposed to appear like to others. That's what I do and have done for years. Sick of it.

I have noticed the same thing to a degree. While I have never been able to "mingle" successfully nor develop normal social relationships due to autism, I had noted that the alexithymic tendency seemed to increase as I age. It seems when I was younger, a child perhaps, I had better access to these things.
But here's some food for thought that might be relevant to your situation - I recently found a manuscript I had written probably around 15 years old. And the emotional cues of the protagonist were all wrong. It was as if I was guessing what someone would feel in the situations I created in the story, but it didn't "fit," there was no basis for the responses of the character, if that makes sense. Which reflects my complete deficit of empathy. I had no idea, even then, what it was like to feel those things nor the proper development of those feelings in relation to stimuli.
That's a verbose way of saying that perhaps the alexithymia isn't worsening necessarily, just that your awareness of the deficit is increasing to match the actual deficit. Lots of people spend years in denial about this, convincing yourself that you're actually feeling these things and are fully aware that you are, when in fact you are not. Accepting it and analysing it, admitting it to yourself and acknowledging that in fact you don't experience these things or are not aware when you do, can appear as though it is increasing.

CV, maybe you're experiencing Alexithymia burnout. Every autistic talks about burnout, but maybe that burnout includes Alexithymia. I can remember faking emotions all the time when I was in my 20s. Fast forward to my 50s, and I can remember somebody thinking I didn't get a joke because I didn't laugh; I got the joke, I just didn't feel like faking laughter. Now in my 60s, I'm even worse about trying to fit in. I still follow most societal rules of etiquette (e.g., not talking over people, but every once in a while I still get accused of it), but I think I suffer from Alexithymia burnout (so it feels like my Alexithymia is getting worse).

CV, maybe you're experiencing Alexithymia burnout. Every autistic talks about burnout, but maybe that burnout includes Alexithymia. I can remember faking emotions all the time when I was in my 20s. Fast forward to my 50s, and I can remember somebody thinking I didn't get a joke because I didn't laugh; I got the joke, I just didn't feel like faking laughter. Now in my 60s, I'm even worse about trying to fit in. I still follow most societal rules of etiquette (e.g., not talking over people, but every once in a while I still get accused of it), but I think I suffer from Alexithymia burnout (so it feels like my Alexithymia is getting worse).