Zaid Alsalami, Shaykh Dr Zaid Alsalami is an Iraqi born scholar, raised in Australia. He obtained a BA from Al-Mustafa University, Qom, and an MA from the Islamic College in London. He also obtained a PhD from... Answered 3 months ago

Bismihi ta'ala

If a man was to conduct a secret marriage with another Muslim woman without telling his wife, that nikah he did is considered valid, although it is not advisable in any way, for the many ramifications it will have. 

A spousal relationship is based on trust, transparency, commitment and loyalty. 

With prayers for your success.