Kendall Jenner and Bad Bunny’s romance may have trouble ahead. After the former couple was spotted getting cozy during a New Year’s trip to Barbados, people close to Jenner, 28, and Bunny, 29, fear rekindling their relationship may not be in their best interest. “It’s very up and down — and extremely unhealthy,” a source claimed, adding the supermodel “just can’t quit” the rapper. “When they’re together, they party like crazy and act so in love, but then, like clockwork, there’s drama because he won’t commit,” the insider added. “It’s destabilizing for Kendall, but no matter how many people te…