Summer House’s Luke Gulbranson is getting rid of his engagement ring … for a good cause.The 36-year-old reality star teamed up with IDoNowIDont.com to auction off a stunning Tiffany & Co. engagement ring, in which a portion of the proceeds will go to the Leukemia & Lymphoma Society.Fans of the Bravo series probably remember Gulbranson mentioning his failed 3-year relationship that played a major role in his and Hannah Berner’s budding romance.