I'd like to clarify this, just in case it is not clear to OP.

I think, BLP, that you were referring to her not taking her son with her, without first having obtained permission from the son's father. Yes, in that, I agree with you completely.

I think, BLP, that you do know the difference, and am writing this just in case OP does not.

OP is, herself, entirely free to move wherever she wishes (to any country where she is allowed to live, or even to try living illegally) without needing permission from her spouse or ex-spouse. She can and must make her own choices, she is an adult and her own agent, and can take decisions for herself, and act upon them, and must bear the responsiblity for herself.