4 the moment no one.
at least that's what known by the midea.
snsd's members dont own their time...they are always very busy. + sm forbid them from dating ...so they can give 100/100 in their preformance.
So far it seems like Taeyeon, Tiffany, and Hyoyeon have without a doubt had boyfriends. I don't know about Seohyun, Sooyoung, Sunny, or Jessica who haven't talked about a potential love or pasted lover.