Why won't my baby mama let me see my son more?

My baby mama and I went to court and I have every other weekend visitation. I have BEGGED her on many occasions to visit with, talk to on the phone or just see our son at other times outside of my visitation time. I understand that it is not in the court order but my question is why does she not even let me talk on the phone with him when I dont have him. We have a very strong bond and he has told me on countless occasions that he missed me and wants to talk to me.

Why won't my baby mama let me see my son more?
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