Psychology Students/Psychiatrists: What kind of verdict would you give the following person?

Person A: Made up a scene inside his head at a young age, the scene and the characters involved grew as he did. The characters developed. Person A has a character called XYZ in their heads and they're in love with XYZ. In short: Person A has a Princess charming figment of imagination. The princess charming has a name, a designation and all the specifics.
Now here's the twist: PERSON A KNOWS and understands fully well that Princess Charming is a figment of his imagination and yet he chooses to continue to love her. In a recent appointment he said that if I'm ever forced into a relationship by my parents, I might end up either killing myself or my wife who "even thought of replacing Princess Charming" (He's assuming that this relationship will be forced and the wife will be perfect on picture but horrid underneath)

That raises a good number of flags. What surprises me though is that he's aware of the scene not being real and is in fact quite grounded in real life. This Princess Charming however has impacted his love life because he tries to find the Princess Charming in every woman he meets and if they don't check the boxes, they're never contacted again.

----DONE---Why am I asking this? Recently I started checking out some psych books and my friend and I were having a discussion. So curious.
Psychology Students/Psychiatrists: What kind of verdict would you give the following person?
Post Opinion