How can she become “Mom” to her daughter again?

How can she become “Mom” to her daughter again?

"I’ve been with my husband for ten years and married for 6. He has two children from his previous marriage, including a 13 year old daughter who has lived with him as long as I’ve known her. Within the last few months she’s gone from calling me 'Mom' to 'step mom' or by my real name. It really hurts because I’ve raised her since she was a little girl and I consider her my daughter."