We rationalize the things we feel stuck with. 
It seems like we free up mental space to get on with our lives by deciding things are not so bad, after all.

The "psychological immune system"

Facing and eventually coping successfully with changes can make people go through all kind of emotions that finally lead to them changing their mind, in order to better adjust to the new situations.
Thing that is perfectly normal, as it is easier to live at peace with your current life than oppose it endlessly and know only frustration.

Coping with changes

While most of us generally agree on the fact that individuals do not really change their mind, or at least not that easily, recent research has shown that this is quite inaccurate.
People seem to be willing to change their mind in order to adjust to a situation they did not want at all in the first place: that is to say, they try to find something good in what seemed extremely dark, so they can stand what they are going through at certain moments in their life.

Changing our minds

We usually believe that our opinions are stubborn and fixed. But new research shows that our views, even on politics, are changing all the time – just not for the reasons you’d expect.