Manny's Links
Manny has secretly been pining for Dylan since middle school, though he hasn't always had a name for these feelings. Although he was treated very poorly by him, Manny felt a sense of importance from being the one person who stuck around.
Dylan has no special feelings for Manny, but keeps him around because he's the only constant left from his old life. Manny also reminds him of the frustration that no one else from their childhood decided to stick around, so Dylan takes a lot of his anger out on him.
As Manny starts to learn more about him through Lyla, Dylan feels extremely uncomfortable, almost violated. At the same time, he needs Manny in order to learn about himself (though he doesn't always want to), and depends on Manny to bail him out when his secrets might be threatened. This is also when he finally starts recognizing Manny as an individual rather than a relic of his past.
Might read some of ER's blog posts when he first figures out about Dylan's DID. Might also post questions in some DID forums and have ER answer.
ER has no idea who Manny is.
Manny's feelings about Lyla are complicated. She makes him feel important. She unnerves him. She takes him on adventures. She's a window into what it might be like to be close with Dylan.
While his fondness grows for her throughout the story, he spends much of it conflicted and somewhat forcing himself to be okay with her. He also feels a sense of guilt from learning Dylan's secrets from her, but secretly appreciates the new closeness this causes.
Lyla doesn't love Manny, but the fondness and trust she feels for him spans beyond friendship. And she's plenty comfortable being physical with him; even if she wasn't she has no one else to ask for the kind of intimacy she wants, and she knows Manny wants her (in a complicated sort of way).
Manny is both a means to validating her own self expression, and a trusted ally she can be herself with. Lyla recognizes Manny's crush on Dylan, which she uses to her advantage (but also is why she trusts him).
Finds K's blog while trying to educate himself on DID, and after a few comments (and a lot of K giving far more personal information than is wise) they realize they go to the same community college.
Manny wants to meet K and have more people he can talk with about DID.
K knows Manny as a fan of his blog and, after learning they go to the same community college, is excited at the prospect of having her own friend.