Responses
Imo Lyle's insecurity is the whole point of the main story, what with how we find out the way his grandfather makes him feel not enough on a usual basis. We've seen how he's had those feelings ingrained in him all his life so it makes sense that when something like this happens, which is kinda a key point for this type of pair in this type of universe, he'd be taken over by his insecurity. And it feels like sth that is not easily solvable by falling in love and having a good relationship, more like he needs a lot of therapy. Imo.
We're already in the extra episodes, yet Karyle is still so insecure about his relationship with Ash that he proceeds to jump to his own conclusion instead of talking to Ash about it. Man up man!