You were right to insist on skiing. There are plenty of beach resorts in the world, and they aren’t going anywhere. Snow, however, is only available in season. Miss the season, and you’re left without any skiing. You can go to the sea at any time of year. Winter in Slovenia is especially beautiful. Everything looks like a fairy tale at that time of year, and the sights look very different than in summer. Check out car rentals in Slovenia here: https://getrentacar.com/en-US/slovenia . I’m sure you’ll find a convenient car that suits you.