OK, so I think this gets to the nub of it. Your life revolves entirely around your family and you don't have much going on beyond that family. You had perhaps assumed that your son's life would follow a similar trajectory, and you're hurt that that's not what he wants.
The thing is, OP, most people love their families and enjoy spending time with them while also wanting to pursue their own careers, hobbies and friendships outside of the family. With respect, your life sounds quite narrow and a bit limited. You may be happy with that or you may not, but your ds is not wrong to want something different.
It doesn't mean that he doesn't value his family or that he doesn't love you. It simply means that he has recognised that the world is a big place with lots of interesting people to meet and interesting things to do, so he needs to divide his time accordingly.
I spent most of my twenties living abroad and I saw very little of my parents for most of that decade - occasional visits home, but that was it. It didn't mean that I cared about my parents any less, I was just living my life. And now I'm at a different stage of my life, I'm see my elderly dad every day to check that he is OK.
You need to change your perspective. This isn't a rejection from your ds, or a failure on his part to fulfil his duties as a son. It is simply part of a natural process of him spreading his wings and exploring all that the world has to offer. Be happy for him, and simply let him know that you're always happy to see him whenever he feels like getting together.