For no good reason... for no good reason? Wait until you get to chapter 11. Then you'll see that Sterling had a VERY good reason not to tell Brenna. She goes scorched earth in her revenge without thinking of the consequences. If Sterling had told her, things would have ended up fucked up (and that's an understatement).
You mean that we do not know the reason until chapter 11? Because I'm referring to chapter 7-8 where *spoiler*(I don't know how to do the tag yet, lol) Hunter tries to pretend he's Sterling.
He still messed up Hunter's plan but was one wrong sentence away from *spoiler*. I'm pretty sure most people would pick scorched earth over *spoiler*. Since Hunter didn't ruin him for messing up the plan, there really wasn't a reason to lie to Brenna. Especially, the way that he convinces her she's delusional repeatedly when she keeps asking him and saying she feels like he's hiding something.
If he doesn't trust her enough to tell her (if that's the response you mean in ch 11), I would say that would at least be a good reason to stop pressuring her to take down her barrier to having sex, especially to the point of making her cry, and especially when you know that Hunter is spying. Really not a great look.
Not to mention that it doesn't matter if you're not the person to administer the 'roofie' you probably shouldn't have sex with the people under the influence, especially if you constantly have to pressure them into it. That on top of the number of times he looks to make use of Hunter's cameras etc. And that one of the many reasons he can't rat out Hunter is because Hunter has him on record with *spoiler*, like Kevin did.
He vomitted at the thought of incest in the beginning but by ch 7 Hunter rightly tells him he's a hypocrite that won't share. He really just didn't strike me as the 'hero' , I really thought that was the point. That by the end it was going to end up that Hunter was really his Dad or something and that pretty much everyone in the story was exactly like Hunter, including the readers. These authors like to poke fun at the readers a lot, lol. They know their audience.