Why does my husband feel he doesn't have to say Happy Mother's Day to me?

I have been married 36 years have three grown children. Every Mothers Day is bittersweet for me because quite a few years ago my husband said to me I am not his Mother and he doesn't have to say Happy Mother's Day, That hurt me so much because I am the mother of the three children I gave him. There are strangers that say Happy Mother's Day to me. Through out the day no matter who the person is they wish me a Happy Mother's Day. Should I feel hurt??