Mark Estes wants to “focus on the future” following his breakup with Kristin Cavallari. The 24-year-old TikTok star – who is best known as part of the MontanaBoyz – had been dating MTV personality Kristin, 37, for seven months when they split in late September, and now a rep has claimed that he just wants to put all of his energy into his work. The rep told E! news: “Mark has immense love and respect for Kristin and their time together. He’s focused on the future of his business and his project in development with Vice Studios.” Kristin recently admitted that even though he has been the “best …