I see people all the time people feeling defeated and exhausted when dealing in relationships where someone has some form of mental illness or personality disorder.
The unpredictable behaviours of another can result in one constant manipulating their own personality or walking on eggshells to not be exposed to the repercussion of such personalities . It's exhausting really .
One thing you need to remember is that trying to get logic from a situation like this is not accepting it nor understanding that there is an illness involved . You'll beat yourself up trying to make it normal again .
Over time you can lose yourself amongst it . It's like poison to the soul . You encounter self doubt on a daily basis . It's consuming . Accept the illness is there although you cannot see it physically ... The behaviours are your confirmation . Step above it and remind yourself that you cannot get logic here .
If you can get away from it then you can rebuild yourself .
If you cannot because you are a carer or choose not to then ensure you seek respite and support to stage engaged in the positive aspects of your life that give you strength and allow you to be you free of fear and totally authentic .