I mention this because of the recent Agony Booth review of TFF where the author has a fit about Spock being an only child. Vulcan's are mated at the age of 7. Assuming that Sarek was no different he must have had a wife previous to Amanda who died. Otherwise how would there be an opening for him to take another bride of his choice? Assuming his original betrothal didn't reject him like T'Pring did to Spock. But wouldn't that mean Sarek had a fight to the death and then won the girl? Hmmmm....
Yes, I think you are either the only one or among the
very few who thinks Sybok makes "sense"

.
Vulcan children are "bonded" at age 7-8 (establishing a permanent mental link between the pair), but the couple do not consummate the marriage until they are sexually mature (later for Vulcans than humans) and often not until their first pon farr. Bonding is not a universal practice on Vulcam - in some families it is traditional, while in others it is more common for individuals to choose mates as adults.
As for Sarek - no, he never had to fight another male to the death to win any "girl".
In books and canon, evidence is contradictory whether the "Vulcan princess" was Sarek's first actual "wife" or not. In TNG ep "Sarek", it mentions that Sarek's first wife was a human. In TFF and the novel "Sarek" (I know, not canon), Sarek is indeed bonded to the princess (or priestess, as she is in the novel) as a child and conceives a son with her later. Eventually she "divorces" him when she assumes the role of high priestess, and since Sybok is still a youngster, he comes to live with Sarek, Amanda and young Spock. In the novel "Spock's World", there's no Sybok (thank the Elements) and Amanda is his first wife of any sort.
It all sounds painfully dodgy and unlikely for one of Trek's great characters to me, and I revolt at the idea of a Vulcan "princess" at this late date in the planet's history. The "Sarek" novel's solution of a "priestess" makes a bit (though only a bit) more sense. All this story strain is in aid of explaining the existence of Sybok in TFF, a straining that is just too much for me.
IMO there's no way Sarek ever sired anything that looked and spoke as Sybok did in the film. Unbelievable.
Sybok has to one of the most dubiously written characters, one of the worst cast roles, and one of the lamest ideas to drive a plot in Trek history. Personally, I'm with D C Fontanna, who simply chose to pretend he didn't exist. I've met the actor who played him, Laurence Luckinbill, a nice guy and talented performer, but he's simply dismal as a Vulcan.
I find most of TFF to be pretty lame, so my life is happier ignoring it and Sybok.