Does SO make Mother's Day special?

So my situation is I have two bio kids (only mine) and two foster kids( I am the only one on my license). I have a fiance whom I have been in a relationship for almost a year and a half that lives with us. My question is on Mother's Day do any of your SO that are not bio dad to your kids do anything for you to make it special? Or do they think it isnt their responsibility because the kids are not theirs? If so, what do they do?