I've always wondered why PA got married again. I mean, she already had children & didn't need a man's money to support her, so it must have been for love, right?
I suspect it is because the rumours about PA that had been in circulation since the early days of her marriage to Mark Phillips had become a problem. Even back in the 80s I don't think the RF could deal with the idea of a female member of the RF engaging in affairs. Better to promote the idea of a Finally Happy Ever After relationship. Anne had to be made respectable.
I understand there are rumours of her marriage to Laurence going adrift too.
I suspect the close relationship between Andrew and Fergie story has the same attraction for the RF except in this case to suggest that Andrew has no outside interests. At the same time it solves the problem of Fergie having nowhere to live and couch surfing her way around Europe and America for the rest of her life.