If you say that someone has a guilt complex about something, you mean that they feel very guilty about it, in a way that you consider is exaggerated, unreasonable, or unnecessary.
[disapproval]
guilt complex in British English
(ɡɪlt ˈkɒmplɛks)
noun
a feeling of guilt that is exaggerated, unreasonable, or unnecessary
She was ridden with a guilt complex about her desertion of the father she was neverto see again.
Examples of 'guilt complex' in a sentence
guilt complex
We can stop enabling the victim mentality by overcoming our guilt complex.
Times, Sunday Times (2006)
Defence counsel claimed this was due to a guilt complex because they had lied to the court.
Times, Sunday Times (2010)
This has resulted in a kind of guilt complex and an inability to show any anger at all.
Turner, Janine Behind Closed Doors - advice for families with violence in the home (1988)