I am a separated father with a 50-50 contact split with my son who is eleven . Occasionally I call him on his mother's phone to chat as he has no phone of his own . I found it annoying and a lack of and respect of privacy that she switches the speaker phone on and adds to the conversation or responds to a question I ask my son . Completely over-involved . I would simply never do the same if she phoned on my phone . I should say that she lacks boundaries and completely no self awareness .