In the last 40 years, philosophers have begun paying attention to a fundamental distinction in how we use gratitude terms (Walker 1980–1981; Card 1988; McAleer 2012; Manela 2016a).
On one hand, such terms can be used just before the preposition “to”, as in
Y is grateful to R for φ-ing,
where Y is some beneficiary, R is some benefactor, and φ is (at least paradigmatically) something R has done that was beneficial for Y.
Tony Manela (2016a) calls the attitude expressed by this type of locution prepositional gratitude.
Gratitude Apprentice 