As said in some puranas and in this question, Hanuman will become the next Bramha. Also, as we all know, Bramha's wife, or to be exact,shakti,is Saraswati. Now, the shakti provides power to their respective husbands. In Bramha's case, his shakti is very important as Saraswati provides the knowledge and creativity needed for creation.
However, since Hanuman is a bachelor,he would not marry Saraswati. Hence, will she still exist in the future?
Morever, without her, he would lack the knowledge and creativity needed for him to creation. Plus, he would not have power/energy without a shakti and may cease to exist to. Besides, even Mahadeva (greatest of the gods) requires his shakti to function. Thus will Hanuman be able to create the universe?