ANSWER:

No problem. 

However, this is not very wise as he will have to lie when at other wife’s house and lying is not permissible at all and they would go through a lot of hardship if he dies and when it comes to distribution of his inheritance when the one doesn’t know about the other.

Is it possible for a man to marry more than one woman without them knowing that he’s married to another, as long as they are all treated the same?