Might be wrong...
I feel he thought about it and decided to eventually propose a three-way relationship eventually, as a way to make everyone happy. Not that it will work out, it seems a waste not to make a twist about that. Not to mention the story name suggests thing like that. At least he has the most credit to be called "third party" right now.
Even propose a threeway would be better than directly blackmail Gu to make her leave everything she has to him. It isn't fair. （￣へ￣）
Might be his way of wanting to prove:
"Leave it to me girls.. see I can do it! So how about we do a 3p?"(⌒▽⌒) It's not like he's blackmailing her right now, more like warning them. As he didnt say it himself yet, that otherwise he would snitch on them. At least so far he shown to have good wits.
It would be a waste to have another clische - stupid out of jealousy blackmail.
Its a Yuri so it's not like it should work out.
More like a blackmailing out of greediness, but maybe you are right ^_~
Thanks a lot for the chapter!
This is horrible!! What the heck Sang Hun is always the first to come with these nasty ideas? His greediness has no end. （￣へ￣）