Short answer no. You’re not entitled to gift your family members girlfriend or boyfriend. You can if you want to elect to gift a joint gift. If you were planning on spending between 20-25 anyway, then you can elect to get a gift card to their favorite restaurant for that same amount. Again, this is all up to you and not at all necessary to do.
And I know you asked about people who have kids as well. It’s always customary that if you have to choose to give I would give the kids and maybe make cookies for the family or give a family gift. I was always taught once you have children your gift days are over. My parents still give me things but if they stopped I wouldn’t be mad. The children are the primary. I’ve done family gifts where I’ve given a dvd, popcorn and other snacks inside of a bucket. I decorate it really nice and give it to the whole family to have a movie night on me. So there’s way of being creative and not spend a lot of money. It’s up to you. Don’t be forced to do anything for anyone you don’t want or can’t afford to do.