Koi no Hajime

From Yaoi Is Life:

The recent newcomer at Naitou's work is none other than Tsutsui, who despite being a University student, is also the son of a famous rich man.

Naitou realized how different their common knowledge was as he saw Tsutsui struggling with cleaning material, and greeting the customers as if it was a high-class store. However, against all odds, he embraced the good impression that the hard-working, serious Tsutsui had left on him.

Even so, as Tsutsui tried treating Naitou to dinner and offering him things to become his friend, circumstances caused a mood of servility to sprout between them.

Also included, the love story of Tsutsui's butler, Fujiki.