This has been in my mind for a long while as well. I remember in an interview after SITR, talking about her chemistry with JHI, she told the reporter (or the MC, can't remember) that she was literally asked (by someone) if they were dating in real life. I have a hunch that this someone is HB. Just my guess.
ETA: I know someone may say that it is off topic and in fact I have considered a while before writing it. I ultimately put it down cos I guess people won't mind I say it here in view that HB is the one who win the love of YJ