A great example of a psychological thriller/romance is YOU by Caroline Kepnes. (There is also a sequel, Hidden Bodies, which I have not read). It is told in the first and second person.
Joe Goldberg is a psychopathic stalker in his twenties who has a day job in a bookshop. His stream of consciousness narrative is cynical, judgmental and perceptive with strong views on morality and popular culture - all fuelled by a sense of social inferiority (he couldn't afford to go to college, but is, in his opinion, far better read than the rich kids who could).
Then Guinevere Beck (the "you" of the title), a flirtatious, social media preoccupied would-be writer buys something from his shop. Instantly Joe is smitten and embarks on an obsessive quest to make her his. Breaking into her apartment, hacking into her email and bumping off people who get in his way are all par for the course - after all, no faint heart ever won a fair dame.
Recommended.