Speaking as the child of many ruined xmases due to the parent's own memories and feelings...
Please, please don't dwell on the past and do make happier memories for your own children.
Do all the simple things like making paper chains out of scrap paper, bake together, watch rubbish Xmas movies and tell those god awful cracker jokes. It doesn't have to be a lot but you do have to make a start.
It wasn't until I was an adult and learned that my dad's dad had died on Christmas Day eve (when he was about 21) that my own xmases made sense.
Having to tiptoe round because the slightest sense of discord would mean he would shout and stomp about. Having him practically ignore us and guests for the whole day. The drinking... not to get drunk when we were younger but it made him more aggressive. Spending the whole day with this funny feeling but not knowing what it was.
Dh's xmases were spent with parents who went out to work because they needed the money - the day attracted a higher rate of pay. Once they were old enough, he was left with his brother (10 year age gap) for the day. Dh jokes about it but I can see the hurt of not having his parents home and having fried egg for Xmas dinner.
We have a sen child too so we try and have a pressure free Xmas.
The tree goes up, received cards are stuck around. We bake together. We watch rubbish tv together. Or sometimes we all just do our own thing but in the same house. We invite dh's parents over because we want them to be with us rather than because they are an obligation.
I hope that our children feel they can talk to us too so if they aren't happy, we can help and out a stop to the ghosts of Xmas past haunting our children when they are older.