
He didn't do anything wrong.
When they became a couple Ethan loved Blue as a love interest, but Blue loved him as a brother. Eventually, they shared the same type of love, but maybe Ethan still felt like he had been selfish and forced Blue into the relationship. Ethan felt guilty and that made him even more depressed so he broke up with Blue so as not to hurt him anymore. Because he had so little self esteem, he couldn't believe Blue had reached the same feelings as him and thought that Blue was pursuing him out of pity.
As time passed, he started to see Blue as more of a family member like Blue' family considered him. He also started to feel better about himself, probably because of Jimmy as well.
So now, Blue still loves him as a love interest, but agreed to revert to his brotherly love. It's hard and painful but not impossible for Blue as his original feelings towards Ethan were of brotherly love.
That's my understanding of their relationship so far. Their feelings were never synchronized. Hopefully they will feel the same soon enough cause they need each other in their lives eventhough not as a couple. And I personally think it will be a healthier relationship.
I still don't understand what blue did that made ethan's feelings toward him changed ╥﹏╥