It's so funny that M&M have millions of people wondering whether there is or isn't real romance there. It is good for their popularity on the show, so they are wise not to confirm or deny it. Just keep them dreaming or guessing.
Perhaps only Charlie, Sharna, and M&M's very closest friends and family know for sure.
If I had to guess, I would say no, not now. But I think there has at least been a lot of mutual attraction in their partnership, and they could pursue something more romantic in the near future once the show ends. If not, they will likely stay good friends at least.