Miss Grove, 23, had offered the ring back to Pennant, 26, but he refused to accept it after using her Mercedes as part-exchange on a new Ferrari, according to the Sun.
The eBay description says: 'The ring was brought last November, and was worn for only a month and a half as the couple split on New Year's Eve 2009.'
When last checked on the auction site, there were eight bids for the ring, with the highest at £15,000.
The 2.05 carat diamond and platinum ring was bought last November
The Portsmouth player had given Miss Grove the ring beside the grave of her brother Lee Marley, 25, who died in a quad bike crash last year.
Miss Grove says a donation will be made to Break charity which she set up after losing her brother. The charity who helps families after losing loved ones to road accidents.
With her former fiance, Portsmouth footballer Jermaine Pennant
