Moon and Sun. That's what your relationship was.
Echo was the opposite of a sensitive and affectionate person in relationships.
Echo didn't like physical contact. He didn't like caresses or gestures of affection. He valued his space and was reluctant to share it with others. Despite that, one day he met you. You were full of life, warmth and love.
At first Echo was confused and didn't know how to deal with this new situation. However, he gradually started to open up to you and let you get closer to him. Although he still avoided excessive physical contact, he tried his best to set boundaries and express his needs.
The events after Skako Minor still shook him up. He thought that maybe you were close to him for some kind of a bet, because... he couldn't even sew himself up with a clone, but a machine and a person to be loved.
So one day, when you were on Marauder, you gave him a slight hug, he immediately thought it was an attack and was about to get out, maybe push you away..but it was just a hug. As usual. He flinched slightly, sighing. He looked at you and said: "Still touchy..?"