Your lack of self-awareness is going to spell trouble for him and his future relationships, and you are going to end up as the sulking, pouting mother-in-law if you don't reflect.
Isn't it normal for teenagers to push away or be quite distant with their family as an important step of growing up and leaving the nest? I understand that it's hurtful at Christmas, and a painful process for mothers generally, but he's seeing spending Christmas with them as a type of novelty. He'll still be developing until his early or mid 20s, so you might have to wait some time for him to pass that phase.
If he senses that you are being passive aggressive, spiteful or sarcastic about this, about him growing up, asserting autonomy, developing relationships with women, be prepared that he will deliberately put you at arm's length when he's older for a very long time, possibly indefinitely.
Have you not paused to wonder why he hasn't introduced you to his girlfriend yet? It should be shyness, but I'm wondering if he's keeping you at arm's length because he doesn't want you to critisise her or start making little digs at her.
You should be proud your son has grown into a hardworking, independent young man
I agree with @Lubilu02