One coping mechanism I have evolved is to just not care about anything.
(1) I don't care if you shag other women, because I don't love you that much
(2)I don't care if my ex does not answer my requests about my child, because my opinion doesn't matter
(3) I don't care if I'm not promoted, because I don't deserve it.
And so on which eventually leads to a loss of self...
I think I may be in a dark place at the moment, but I am too busy coping to even try to get out of it.