Tsar Alexander II's bride choice fell in that category.
As a crown-prince he fell for Pss.Marie of Hesse-Darmstadt who was far from being the ideal d-i-l for his parents, being notorious that she was not the daughter of her official father, the Grand-Duke, but her mother's illegitimate daughter although accepted and recognized by her husband.
In the end, Alexander could marry Marie.
Another one was Philip of Greece ;
He was not the ideal son-in-law for K.George VI and Q.Elizabeth.
So soon after the end of WW2, he was too german in his origins and had that "uncomfortable" family with so many members or sympathizers of the Nazi party.
Luckily, Uncle Dickie came in his rescue, washing the rotten part of his bio, the family was ostracized and Lilibeth showed her stubborness.
In the current generation there are several cases of marriages that went against parental opposition, but in these cases, the marriages were unequal.
Crown-Prince Harald and Sonja - Firm opposition from King Olav for years.
G.Duke Henri and Maria Teresa Mestre - the family was pressing to one of the twin brazilian princesses or Pss Catherine of Limburg-Stirum, eldest daughter of the Counts of Paris.
Felipe and Letizia - need to say more ?
When it comes to opposition to royal marriages, one typically thinks of cases involving "unequal" unions -- especially to commoners. But in the past, there were plenty of royals who found *love* with fellow royals whom they couldn't marry, because of personal or political opposition. The official historical record may state that some King/Prince X married Princess Y, but she may not have been his first love or preferred choice of royal bride.
Either that or a pair of royals DID marry -- but against family opposition or without the (initial) requisite consent of the sovereign. We've seen this happen in Russia (e.g. Ducky and Kirill) and Spain (e.g. Beatrice and Alfonso). Of course, these unions usually did eventually get approved (and presumably, retroactively).
So I got to wondering about specific cases of unions contracted against parental opposition in particular -- even though the unions were, in the end, dynastic. Is it true, for instance, that both King Haakon VII and Queen Maud of Norway initially opposed the marriage of their son the crown prince (future King Olaf V) to Princess Martha of Sweden? The explanation I heard was that they had nothing against the bride personally: it's just that the pair were too closely related. It wasn't just that Olaf and Martha were first cousins; it was also that they were multiple generation first cousins. After all, Olaf's own parents were first cousins; and Martha's parents were first cousins, once removed.
I read that the king and queen's preferred choice of bride was Princess Ingrid of Sweden -- a second cousin (like Olaf, a great-granddaughter of Queen Victoria of Great Britain; but unlike Olaf, she did not descend from King Christian IX of Denmark). Is that true? Did those two meet, and did anybody try to foster a match between them?
I also read somewhere that the future King Ludwig III of Bavaria and his consort, Archduchess Maria Theresia of Austria-Este, opposed the marriage of their eldest son, the future Crown Prince Rupprecht, to Duchess Marie Gabrielle in Bavaria. The reason was that the two presumably were "too closely related" -- notwithstanding the fact that they were only second cousins, once removed. Of course, the marriage did proceed -- in 1900, when Rupprecht's grandfather, Prince Luitpold, was still serving as regent of the kingdom, and hence was the acting head of the house of Wittelsbach. So the matter was not entirely up to his parents alone.
What exactly Luitpold personally thought of the match is anybody's guess: all we know is that he must have given his dynastic consent to the union. He certainly would have had the power to side with his grandson, overriding the opposition of his son.
I said son, because evidently his daughter-in-law did eventually overcome her opposition to the union -- meaning that she had initially objected exclusively on the grounds (later proven to be unfounded) of close inbreeding. She even intervened to override her husband's objections, to allow the marriage to take place -- notwithstanding the fact that (once again) her father-in-law was the one who had the ultimate say on the matter, to grant or withhold consent.
Just why the then-Prince Ludwig was against the match is baffling; but the implication in the article I read was that he had hoped for a *better* catch. This doesn't make a whole lot of sense, since by then the stock of the ducal branch of the house of Wittelsbach (the non-reigning, genealogically junior line) had risen sharply. After all, the said branch by then had produced two queens (i.e. Austria and the Two Sicilies), with a prospective third (i.e. Belgium).
Does anybody know more details about the matter, whom exactly the future King Ludwig III had in mind for his son, whether Rupprecht was linked to anybody else, what other prospective royal brides were seriously considered?
One presumes that he had his pick, since at the time there were many eligible princesses available on the marriage market. Moreover, the stock of his family had risen sharply, since by then "Mad" King Ludwig II (his godfather) was dead, the equally insane King Otto was incarcerated in a mental hospital, and the signs looked positive for the Bavarian royal succession to eventually pass to the line of Prince Luitpold (third son of King Ludwig I).