
In the drama CD flashback, you can hear him saying “Yada” which basically means “I don't want to.” So I believe the guy betrayed him by taking Kei someplace where Kei thought it'd just be that guy. But other men were they and they raped him. And then maybe he was offered or coerced into doing AV and he felt dirty already so he accepted or gave in.

True. I also feel like he was somehow forced or manipulated into it. The older guy definitely had other intentions and did not love Kei or doing porn would have never happened. That's why Kei now calls himself a "hard bottom" because of those times and feels about it all and thought the seme will leave him. I hope Kei doesn't end up sleeping with the black haired guy and ends up in a bad situation. This is most likely going to happen.

Yeah, I hope that other guy (cute doggy one) will appear in the last moment and save Kei from making bad decision. Especially considering the fact that the goatee dude is from porn industry (he's a director or what?) and wants smth from Kei. In ch1 Kei's friend from the bar warned him about those shady guys from the studio among whom was that guy from last chapter.
NOOOOO!ヽ(`Д´)ノ
Don't go with him, honeeey! T_T
I hope that asshole will not bring him back in AV industry T_T And that old man from Kei's memory... I get this feeling that it's him who brought him in AV in the first place. Common thing in manga "I will sacrifice my body to pay the debts of my beloved one" or some similar shit (︶︿︶)
But it's just me guessing ╮( ̄▽ ̄)╭