What is the ruling on someone who supplicates to Allah to prevent him from entering a certain place if he is a Muslim and married, then he goes there, while not intending disbelief or divorce? And is his entry considered an answer to the supplication? And is this supplication permissible in the first place?

A Muslim is not permitted to doubt his Islam, and it is forbidden for him to make an exception in his faith out of doubt. The phrase "O Allah, if You consider me a Muslim" reflects hesitation and suspicion, and indicates a [whisper from Satan] (waswasah) that must be ignored. Furthermore, this expression is not befitting when addressing Allah Almighty, as scholars have prohibited statements even less severe than it. This supplication contains the meaning of testing Allah Almighty, which is not permissible. As for entering the place after the supplication, it does not result in disbelief or divorce. One must ignore [whispers from Satan] (waswasah) and seek Allah's help.