Lost Dean and Sam story

[babyreaper]

This story was about Dean being on his own because he and Sam had argued and Dean was in a bad place, Dean met other hunters, an older man and his niece, they fell in love and eventually went back to Sam and the bunker I think. There were some pretty powerful demon around as well, a male and 2 females I think. Dean becomes a demon, can't remember why and he is really nasty,
has lots of woman and attempts to kill Sam and his girlfriend. I remember that Sam has feelings for Dean's girlfriend as well, from when Dean was a demon and they spent a lot of time together. His girlfriend sells her soul to help him. They have a battle near the end with the male demon and Sam and Dean die and the girlfriend goes to hell, but I think Crowley helps her get out and up to Heaven. Does anyone recognize this story, thanks in advance to all who reply