What the Book says about a person who has been wronged
People carrying this often believe two things at once. That they must keep it entirely to themselves. And that they should have been able to bear more than they have.
The Qur'an speaks about the one who has been wronged and about the burden a person is given, and neither passage reads like an instruction to stay silent and carry more.
Telling one person who is safe, or a professional, is not backbiting the way it is usually thrown at you. Where exactly the line falls between complaining about a person and seeking help about a situation is a fiqh question, and it is worth putting to a scholar once, plainly, so that you can stop guessing.
Qur’an and Sunnah
لَا يُكَلِّفُ ٱللَّهُ نَفۡسًا إِلَّا وُسۡعَهَاۚ لَهَا مَا كَسَبَتۡ وَعَلَيۡهَا مَا ٱكۡتَسَبَتۡۗ رَبَّنَا لَا تُؤَاخِذۡنَآ إِن نَّسِينَآ أَوۡ أَخۡطَأۡنَاۚ رَبَّنَا وَلَا تَحۡمِلۡ عَلَيۡنَآ إِصۡرࣰ ا كَمَا حَمَلۡتَهُۥ عَلَى ٱلَّذِينَ مِن قَبۡلِنَاۚ رَبَّنَا وَلَا تُحَمِّلۡنَا مَا لَا طَاقَةَ لَنَا بِهِۦۖ وَٱعۡفُ عَنَّا وَٱغۡفِرۡ لَنَا وَٱرۡحَمۡنَآۚ أَنتَ مَوۡلَىٰنَا فَٱنصُرۡنَا عَلَى ٱلۡقَوۡمِ ٱلۡكَٰفِرِينَ
God does not burden any soul with more than it can bear: each gains whatever good it has done, and suffers its bad- ‘ Lord, do not take us to task if we forget or make mistakes. Lord, do not burden us as You burdened those before us. Lord, do not burden us with more than we have strength to bear. Pardon us, forgive us, and have mercy on us. You are our Protector, so help us against the disbelievers.’
Qur’an 2:286
۞لَّا يُحِبُّ ٱللَّهُ ٱلۡجَهۡرَ بِٱلسُّوٓءِ مِنَ ٱلۡقَوۡلِ إِلَّا مَن ظُلِمَۚ وَكَانَ ٱللَّهُ سَمِيعًا عَلِيمًا
God does not like bad words to be made public unless someone has been wronged: He is all hearing and all knowing
Qur’an 4:148
Translation: M.A.S. Abdel Haleem, The Qur'an, Oxford University Press, 2004.