Some people aren't brought up to think of anybody outside of the immediate family when it comes to birthdays and Christmas. My mother was somebody who made pies for a few neighbours if they were poorly, gave them bread warm from the oven and always gave a present to them at Christmas. Some families don't DO birthdays at all after the children get to an age when they're working.
I think if your husband's comfortable with this that you stop sending cards and presents for birthdays.
I was woken up in France as birthday cards, Xmas cards are a NO (except maybe a garandparent to grandchild) and presents outside of immediate family a NO too. I still send birthday cards and Xmas presents to close friends here but get nothing in return. Like you, I wonder why I bother, but I'd feel unchristian not doing it!