Shift your focus onto the time you and your children have together, rather than on the time you don’t.
If you don’t have your children on Christmas day, you could have an alternative Christmas on another day, with all the trimmings. Ultimately, Christmas Day is just a day, and you can have yours whenever you want.
Your children will almost certainly love the idea because they get a second Christmas. Get ideas from them about things they’d like to do, traditions they’d like to start. Focus on arranging a few things you will all enjoy.
Your children will take their cue from you. If you are stressed and negative, they will be too. If you are angry and resentful, they are likely to feel conflicted and stressed. When you are upbeat and make plans to do things that you all enjoy in the time you are together, they will do the same. When you frame this new reality positively, they will follow your lead.