All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
Your wife has no right to ask for the invalidation of marriage without a sound reason, and it is not permissible for her parents to incite her to do so, as this is encouraging her to spoil the marital relationship with her husband. On the other hand, you are not obliged to accept her request or divorce her unless you wish to do so. Therefore, you should endeavor to solve the problem and reconcile as far as possible.
However, you have the right to refuse to divorce her until she gives you a ransom and the like, as Allaah The Almighty Says (what means): {And do not make difficulties for them in order to take [back] part of what you gave them unless they commit a clear immorality [i.e. adultery].} [Quran 4:19]
At-Tabari said (about the interpretation of the above verse), “…unless they commit a clear immorality [adultery] or use bad language for you, and they deny you your rights over them, then in this case, it is permissible for you to deny them their rights so that you take back some of the dowry that you had given to them if they ransom themselves with it.”
For more benefit, please refer to Fataawa 131855, 157275 and 158409.
Allaah Knows best.