Some men also avoid taking their girlfriends to the family dinner or event during the holidays. This is especially true if he has not known you very long. My friend Kenny used to go through this every year. He always meets new women around the holidays and then all of a sudden, it's Christmas. Oh no! What is he going to do? He definitely does not want to take this new girl to any family function.
If this is the case with your new man, don't hold it against him. He is just not sure he wants them to meet you yet, and so he is being cautious. It may not be a big thing to you (it's just dinner, you might say) but to a man, it means a lot.
Of course, if you have been dating this guy awhile, maybe he does not want to give you the idea that he is getting serious by allowing you to meet his folks. Or it could be that his family has some issue he is not ready to share with you yet. Just don't assume anything; it's best to talk it out.
Instead of worrying about why you can't meet his mom and dad, why not ask him to come over for dessert after he has dined with his family? That takes the pressure off him and could put you in a better position for future holidays, should your relationship continue past New Year's.
But let's say you do get to that event or dinner. How do you present yourself? Be on your best behavior! Remember the old saying, "the apple does not fall far from the tree"? Well, he is probably an extension of someone in that clan, and it's best to be kind to ALL of them. Also, pay attention to how he relates to his family members. If he is markedly different around them than he is around you, that is the real him coming out — take notes!
I find it is also a good idea to volunteer to help his mother do something — anything — so offer your help; it's just good manners. And don't start asking a lot of questions about him. If Mom likes you, she will tell all before dessert!
Here's another important piece of advice: DO NOT DRESS LIKE A FLOOZY! Trust me, your clothes tell a lot about you. If you are normally a bit on the flashy side, tone it down. If you are conservative, pull out that dress that goes below the knee, and don't wear anything that accentuates your breasts. Keep in mind that your man is still his mother's little boy!
And one more thing, do not get involved in any family disagreement that may take place. DO NOT. That is his family issue and he needs you to allow him to handle it. You cannot win, no matter whose side you take. So just keep quiet!