Paranormal Romance and Urban Fantasy are like kissing cousins. Considering all the vampires and werewolves involved, maybe that should be biting cousins.
The big difference between Urban Fantasy and Paranormal Romance is usually where the focus is placed in the story. It’s not that Paranormal Romances can’t include an other-than-human hero or heroine, or that the main character can’t be solve crimes in the supernatural community. Likewise, there are urban fantasy series where the hero or heroine does manage to combine crime-fighting or beast hunting with a successful love life…eventually.
I think the poster boy for Urban Fantasy is Harry Dresden, from Jim Butcher’s Dresden Files. In the first book in the series, Storm Front, Harry is the only wizard listed in the Chicago telephone directory. Harry is a private investigator, and the focus of all the stories in the series is on Harry solving whatever crime or other dastardly deed has threatened the peace of his city. Occasionally, Harry’s love life is less than awful, but it never lasts long and usually ends badly, tragically, or both.
There are urban fantasy series where the point of the story is for the main character to solve crimes, or to figure out who the Grand Poobah of evil is, or determine who is really out to get him or her, but, along the way, there is a long story arc where he or she has this unresolved sexual tension thing going with someone that slowly (sometimes very slowly) gets resolved over the course of several books. (Think Castle on TV) The Kate Daniels series by Ilona Andrews is one of these. In Magic Bites, Kate starts out as a down-on-her-luck mercenary in an alternate version of Atlanta where magic and technology fritz on and off. She begins by hunting down whoever is responsible for the death of her guardian, but along the way, she becomes involved with the Beast Lord of the City. There’s a mystery in every book, but it takes 4 books plus to resolve the romance.
Last, but definitely not least, there are the out-and-out paranormal romances. It’s not a paranormal romance because one of the love interests is a vampire, or a werewolf, or whatever. A story is a paranormal romance because the point of the story is to get to the Happily-Ever-After, or at least a Happy-For-Now, in a setting that includes an alternate version of the world we know, usually by including those vampires or werewolves, but not necessarily.
Nalini Singh’s Psy-Changeling series is definitely paranormal romance, but there are no vampires, at least so far. (Book 12, Heart of Obsidian just came out) Starting from the first book, Slave to Sensation, Singh introduced readers to a near-future world where three “races” battle for domination of the Earth; the Psy, an offshoot of humans with extremely well-developed psychic powers but cut off from all human emotions; the Changelings, shapeshifters; and underpowered original recipe humans. While there is an overarching story about the breaking of the total emotional Silence imposed on all of the Psy, and the worldwide effects of that break, each individual story in the series is about one couple and their HEA. The romance comes first.
And there you have it. Urban Fantasy=case-solving first. Paranormal Romance=Love story front and center. Try one and see which flavor you like best!