DH and I can both do a great roast dinner or Christmas dinner. We absolutely hate cooking together though so we do roasts on our own but as Christmas dinner is a bit more faff, we do tend to do it as more of a joint effort.
Christmas dinner isn't difficult in terms of technical cooking skills, but there is an art to getting the timing right. If this is something you struggle with, write a timetable of when things need to be started and when they've finished.
With our Christmas dinner, I tend to prepare and cook or semi-cook the stuff that can be done in advance, so that a) it's less preparation on the day and b) it frees us space in the oven/on the hob. Things I'll make in advance are:
braised red cabbage - my method takes a good couple of hours so I'll do this a week in advance and then freeze it
stuffing - nothing fancy, just a packet of Paxo with a packet of sausage meat and some extra fried onions added. I prep this a day or so in advance, cover with foil and put it in the fridge so that it just needs shoving in the oven to cook whilst the turkey is resting (I don't like stuffing cooked inside the turkey)
carrots and swede - same as the red cabbage, I'll cook and mash the week before and freeze
other veg - this will be prepped the day before
Roast potatoes do take some practice to get right but if that's not your forte then Aunt Bessie does some cracking roasties!
A good timetable really does make all the difference with Christmas dinner, or indeed any roast dinner! Preparation in advance also makes it much less overwhelming.