I got a bit curious when I read this. Are you saying you don't do Christmas/Yule at all? Or Easter? Summer solstice? You don't even get a pumpkin for Halloween or at least watch a scary film? So if not Western, do you celebrate ... Eastern holidays?
To me, these are just holidays to mark the passing of seasons, which is something humans have done for aeons. They are festivals for spring, summer, autumn, winter. I feel like these celebrations satisfy a sort of primal need. People need parties! Also, partly I celebrate because I'm a dad and children enjoy it, partly so we can maintain family relations, partly because it brings back fond memories of good times had. Myself, my wife, our daughter as well as my parents are atheists, so to us there is little Christian about these holidays, although we did go to a Christmas pageant a few years ago - partly because of the donkey that came from the local donkey sanctuary - my daughter is very interested in and fond of animals. And my daughter is rehearsing a Jesus-y Christmas recorder song. There is no escaping that we live in a culturally Christian country!
BTW, very sorry to hear you lost you partner.