This is difficult since it does not just involve you.
When my own holiday spirit is elusive, I go away for the holiday. I have had wonderful Christmases at the ocean walking on the beach with no Christmas stuff around. Just quiet present opening, immediate family, and time together.
Unless you can get the family on board with that, it is an issue. First, if you have children, I find it easy to rediscover the magic of Christmas through their eyes. What about asking your son to help you with the lights since he’s older this year? (hypothetical since I don’t know your situation) Perhaps take the whole crew on a trip to the woods to find your own tree (do not get stuck like that hapless West Coast couple did). Could you get the kids to buy toys for Toys for Tots or buy and wrap for another program for kids in need?
Is there something that you found especially memorable or magical in your life about Christmas at one time? Perhaps you could recreate that activity and add it to your family’s celebration while telling your kids about its meaning for you.
You also don’t say why you are not feeling it this year. Is that something you could share with your wife? Communicating it may help you feel better or, at the least, it lets her know the place that you are in so she can support you as you go through the holidays.
I often have trouble this time of year. I am OK so far, but when I get closer to the actual day I am going to be feeling the absence from family and friends (often it is just the idea of that and not the actuality of it that weighs on me) as it is our first Christmas in a new state.