How do I learn to love Christmas season again?

Christmas season has turned shitty for me since that was the day my mum told my dad she wanted a divorce. It broke me, my daughter's second Christmas and this happened. I feel as though I can't deal with this season because of the negativity from back then.. I have a loving family of my own and my eldest daughter shares the day with her dad and then it's just me,my youngest daughter and my partner.. I feel as in letting my youngest daughter down, I don't want to celebrate I don't want to even think of the day I want it to be over as soon as it starts..
Im the one who wears the heart on the sleeve so it really affected me, I didn't want to be involved in the mess, but it still hurts and annoys me that this time of year should be fun and happy times but it's not..
How do I make it fun again so my children don't miss out?