I do not have such experience. However, I have been with my husband for ten years. I wonder if something similar could happen. I imagine if it did, it would only be out of habit (frequent calls, seeking advice, etc). If this is new, he may be going out of his way to show her she has nothing to fear, that he loves her the same as he always has.
In a relationship with Armani for ten years. New to the poly world and excited. Living in New Orleans...