I can't wait so see hour our devious little S queen is going to handle this. She wants to see him cry, so the best way to do that is for her to, as she said earlier, stand firm and call him a cheater. Going along with him loses her the initiative.
But I have a feeling that, with polygamy being such a common thing in otaku media, with characters frequently bending over backwards to make it happen, she will go along with it because it's what the audience has been conditioned to expect. Then again, things like School Days exist...
Thanks for the scanlation.