I do feel for Mark, he always seems very uncomfortable with the camera being shoved in his face, and he's shown clear annoyance with Christian and Frankie's behaviour at times, but at the same time, he is choosing to be there/put up with it. He's gone along with the plan to have another child, build a house, go on holiday for 3 months etc etc. If he was truly unhappy he would do something about it.
I'm not even sure that he did tell Christian to put the phone away and spend more family time on holiday, or if that's just what Christian said to explain his absence when he was clearly having a sulk about tattle. Because now he's posting heaps again.