Damien Maslin

Don't read the spoiler if you haven't read all the books yet.

Spoiler:

I personally think he is pretty cliche. He is kind, intellectual, interested in clothes and musicals. That is pretty stereotypical gay. And sadly he is often reduced to being just gay rather than a gay character. To be fair I did look at him rather annoyed from the beginning, because he is potrayed as a non-girly gay character, while clearly being a very feminine gay guy.
There is nothing wrong with being a feminine gay guy(or a feminine straight guy, for that matter), but the book talks far to many times like he is the most manly gay imaginable. And honestly that kinda kills it for me.

And Jack and Damian were a such a shallow couple. They were both gay so the female characters assumed they would end up dating and they did.
The only bonding between them we got was that they talk about both liking Harry Potter. One thing if that was a polarizing book or a secret tipp only hardcore readers knew, but Harry Potter was the most mainstream book of the time.

It doesn't work like that with gay people! They are just as diverse as heterosexuell people. Being sexually compatible does not mean you're automatically compatiblle in personality and/or interests.
I do understand how difficult it is to introduce a new love interest for a character(especially with a sexual orientation out of the norm) without making it obvious, but keep in mind how little time a single novel usually adresses. Damian and Jack go from strangers to the steady couple without ups and downs in less than a week.

I can't claim to be all familiar with the topic and yet I was also bothered by the inconstancy of Damien's character. I never gave much thought to his relationship with Jack, because it never interested and I think you hit the nail on why it didn't. Other gay character introduced, BOOM, gay relationship. Since the first few books were told from Zoey's perspective I could accept that there were some behind-the-scenes moments but it is the rushed nature of it that makes it unbelievable.