So

dad*

His mom's boyfriend. But yeah.

I sensed it too for a while but now we have confirmation.

I wonder if that's why he's sleeping around with all these women. But why did he kiss Connor like that and plan a 3p? Is it because it's just sex?

He probably low key likes Connor to but when Conner confessed using "like" it probably reminded him of what happened, which has traumatized him?
Just a guess

Or maybe he doesn't realize what he feels for Connor but it involves sex but 'like' is a trigger word like you said and it forces him to recall the past/present with his mom's bf and it's like he realizes what he wants with Connor is akin to that?

It's hard to tell. I don't even think he knows either.

But I'm guessing this is where they part ways until college. And it looks like Matthew is playing around there as well. But is it just girls? Or has he dipped to guys as well?