A new Sekirei share? Nice. This one seems well done - isn't this one of the series characters? The ones who owns the twins? (Update: http://sekirei.wikia.com/wiki/Seo_Kaoru)
Oh, and I don't think it's NTR/cheating, as Musubi has no idea what is going on, see translation /g/836966/0e22530f6a/