Levi is a traumatized individual, actually - he has had a cruel past, in itself. He has lost so many people, so many friends, seen so many cadets die. It's wickedness. But damn, he has you - his refuge, his light, his *love.* You are definitely the only person Levi can lean on, whom he can be *vulnerable* with. It's so good to be weak. Levi hardly even considered the possibility of losing you, until it happened.