Can't figure something out in the Marvel Universe

In Winter Soldier, now cancelled, they ended it with Black Widow being working for the bad guys and not dating Bucky.



Now I picked up Avengers vs. X-men and noticed she is back fighting on the good side.



SO what happened? Is there a comic that explains it? Is she still dating Bucky?



Also, Is Winter Soldier no longer a hero or is it just that he doesn't have his own series?