obsessive
ob-ses-sive
noun
A person who is excessively preoccupied with a particular person, idea, or thing.
"He's a real obsessive about his fitness regime."
adjective
Excessively preoccupied or concerned with a particular person, idea, or thing.
"She has an obsessive need for perfection."
Thesaurus
Synonyms: obsessional, neurotic, psychoneurotic