I'd really like shlokas from scriptural sources to verify your ideas. And as the question states, what is the difference in relationship that a son has with his mothers, his human mother and his divine mother. Just to not get me wrong I know the relationship itself is divine, but I'm just pointing out the divine mother to be maa adishakti, one who is mother of all mothers.
I do have some points already noted, the divine mother is not tied to worldly bonds and hence might be free from any aspiration, expectations with her son, and she is equal and justice to everyone and not just her any one son These types of differences are qualitative differences. Another type of difference is a boundary difference which is in how we interact with our mothers and are blessed with their care, love and nurture. There might be other types of differences.
I am not asking what is the difference between the two mothers as one is just a smaller part of the divine, what I am asking is the differences and types of differences that exist in the relationship we have with our two mothers.