As NGalitzine says, one problem for Sarah in the couple moving on is definitely the prospect of losing her title. I wouldn't describe it as a "meal ticket" as *I think Sarah's commercial success (books, TV, speaking engagements, etc.) are down to her own talent and hard work, but I do think that being Duchess of York is part of her "brand", and her prestige and earning potential would be lower without it. In a way, she's trapped - obliged to earn how own living, but (at least partially) dependant on her royal past in order to do so. Nevertheless, I'd love to see her find happiness with another man, and if he was wealthy enough to support her, so much the better.
If she hasn't remarried by now, I doubt she will. None of her relationships have led to marriage in the past.
Andrew came close, but he has to be extremely cautious in his choice so it doesn't end badly, and it isn't just anyone who can fit into his lifestyle.
Of course the title is a meal ticket; who would publish her (really derivative) books, or want her as a speaker, if she was just plain Sarah Ferguson?