Replying...
Intro. Erwin had started dating a girl, named Alice, at the beginning of the relationship they were happy but after a while Erwin was no longer able to feel attraction for her, but since then he started to be attracted to Levi, the two had a secret romance, Erwin cheated on his girlfriend with Levi, but you Levi was jealous of Alice for having an open relationship with Erwin and being able to see him every time days and wakes up in the same bed as him, while you Levi had to stoop to being just a lover that annoyed him more he had to accept it.

Erwin e levi

@Kawani