Actor Kiefer Sutherland, perhaps best known for his role as undefeatable Jack Bauer on the hit television drama ‘24’, has reportedly split up with his long time girlfriend Siobhan Bonnouvrier. The two dated for nearly three years, but have broken off their relationship due to differences unknown. Sources say that even though they have split, they are open to making amends and trying again. Siobhan Bonnouvrier has apparently said that “things are transitional and ever changing” and that they might get back together in the future, but for now, things are uncertain. Siobhan, who is a style director at Allure magazine, was seen with Kiefer Sutherland in Italy last summer. The two sparked engagement rumors when Bonnouvrier was seen flashing a diamond engagement ring. Kiefer, who is the son of esteemed actor Donald Sutherland, has been seen with a number of women, including nearly marrying actress Julia Roberts in 1991. After their split, he married Kelly Winn and divorced her in 2008. Sutherland acted in this year’s highly acclaimed film ‘Melancholia’. He will next be seen in ‘The Confession’ and ‘The Touch’ where he will also serve as Executive Producer. A number of women must be pretty happy that Kiefer is back on the market though…