Amber was pretty reasonable the entire first season, right up until she reveals she had known Mark was Invincible for weeks. She acts like it was completely unreasonable for him to try to keep a secret identity, and it also makes the whole fight after the Re-animan attack complete bullshit and manipulation on her part. It still doesn’t excuse Mark’s behavior as a boyfriend to her, and it doesn’t mean lying to her for several months of their relationship was ok, but it is definitely shitty on her part too.

Amber mellowing out after a) Mark stops lying to her and starts including her in his superhero life and b) Mark becomes traumatized after his fight with Nolan does make sense. It does start setting up the concept of their relationship getting strained by Mark being a superhero, which I think is nice. Now that their relationship is more honest and less combative, there is an opportunity to actually explore it as a relationship between someone who didn’t sign up to date a superhero, and a superhero who will never be able to put being a good boyfriend over saving lives.