What do you consider real, OP? Something material? If that's the case, then you as an individual are not actually real either. Sure, you have a body and a mind, but your center of being is illusory. A chemical reaction that makes matter and energy aware of its own existence.
We exist, but we exist in more than just matter. We are thoughts and ideas formed from that matter. So what about the ideas we have that are separate from our actual being? They don't have a physical form they can inhabit, but they still inhabit us just like we inhabit ourselves. Waifus are ideas. They are innate personalities shared between individuals until someone finds them so appealing that they hold them in a special place in their hearts.
But these ideas aren't aware, so they cannot truly be real in the same way we are. It's not like you can incubate these ideas within your mind and allow them to flourish into autonomous personalities that you share a physical form with, therefore making them real. **That's what I would say if I hadn't already done it.**