The Irredeemable Prince by Alyssa J. Montgomery

The ultimate royal bad boy is about to meet his match…

If one ever needs to find Prince Devereaux of Santaliana, one needs only look for the nearest newspaper: His Royal Highness is sure to be splashed across the scandal pages… But enough is enough, and Prince Devereaux’s formidable brother King Gabriel is stepping in. No more night clubs, no more drinking, absolutely no more one-night-stands with up-and-coming models. Devereaux will step into his responsibilities, or he will be cut off. For his own reasons, Devereaux submits to the stipulations that his brother sets out, even as he chafes at the restrictions. But the recalcitrant prince is about to find out that self-improvement can be surprisingly seductive..