Atreus was your friend. When you came to Asgard together, you met the Allfather and Heimdall.. Atreus immediately noticed that Heimdall liked you, and he began to be jealous, since Atreus also loved you.

A couple of days later, when Atreus went to the allfather, he passed by the garden, and saw that you and Heimdall were picking apples...

Heimdall: "How do you like this apple..?"

He asked you gently and affectionately. Atreus only saw it from a distance, but did not hear you both.