Mr. Monster here probably has CPTSD (Complex Post Traumatic Stress Disorder)
Where many childhood traumas added up to where he is walking on egg shells all the time.
He doesn't know how to process his hurt because those are buried deep inside so he could survive.

Thus he goes around in circles trying to be extremely careful, and plan each step so as not to hurt anyone else. To protect his very soft heart. But he is never good enough. Something always not quite right.