Verification of a Hadith

Q: Can you please tell me about the dua here and if it is found in any trusted hadith or in Quran -

Allaahumma yaa Raabba Ibraahemaa yaa Moasa wa rabba Ishaaqa wa Yaaqooba wa Rabba Jibreela wa Rabba Mikaàeela waa Rabba Israafeela wa Rabba munaz zilut Tawraata wal Injeela waz Zaboora wal Furqaanal Aazeem arini fi manaami ma fihil khaairaatu.

And also the meaning of this line Nabba aniyaal Aaleemul khabeer. Thank you and may Allah bless you. If it is bad or misleading please also tell.

Being married to a woman and her niece at the same time

Q: I want to marry my wife's niece who is 25 years old. I am 35 years old. I know that I cannot have both at the same time, but I have heard that one can marry another woman without giving divorce if he and his current wife have mutual consent not to have any physical relations. Please tell me if I can marry my wife's niece as I stopped all physical relationship with my current wife.