What's the difference between the marriages of Gawen Westerling and Lyonel Corbray? Sybelle's father seems to at least have been ennobled, for all that it was too recently for the taste of a landless second son of Casterly Rock, but it appears that Lyonel's good-father is not even that. So isn't he just setting up his future kids for the same sort of prejudice Jeyne & Reynald face, (presuming they survive Lyn [which I hope tWoW enables by getting rid of Ser Pedo-for-Hire])?
Here's the quote!
Petyr Baelish was clear across the Vale, though, attending Lord Lyonel Corbray at his wedding. A widower of forty-odd years, and childless, Lord Lyonel was to wed the strapping sixteen-year-old daughter of a rich Gulltown merchant. Petyr had brokered the match himself. The bride's dower was said to be staggering; it had to be, since she was of common birth.
Alayne II, AFFC
So yes, there'd be prejudice later. Probably a good deal of sneering at the bride and the marriage in general too. But there would also be money in the near future. Lots of money.
It’s also worth pointing out the potential difference in how the marriages were made. It’s as yet unclear why Gawen married Sybell, but given Kevan Lannister’s comment that “the Westerlings always did have more honor than sense” and the WOIAF app’s assertion that “the marriage is rumored to have somewhat sordid origins”, I suspect that Gawen may have felt compelled to marry Sybell after “compromising” her, along the lines of what Sybell engineered later with Robb. In any event, I certainly don’t think (again given the uniform Lannister disdain for the lower-class origins of the Spicers) that Tywin approved of, much less brokered, the marriage beforehand, instead perhaps seeing it as a distasteful fait accompli between a minor aristocrat and one of his own bannermen, technically legal if socially scandalous; he certainly did not like it, but may have thought there were no grounds to have it put aside. (And, of course, those rumors might have been echoed by the Westerlings’ blue-blood neighbors as well.)
Contrast those “somewhat sordid origins” with the marriage of Lyonel Corbray to his (sigh, nameless) merchant’s daughter bride. Where Gawen’s marriage might have been made quietly to save from personal scandal, Lyonel’s wedding was a very openly acknowledged occasion, not just brokered by Petyr Baelish but attended by the Lady of Ironoaks and the Knight of Ninestars (as well as Littlefinger himself). Littlefinger had already financially targeted Lady Anya in a way she couldn’t escape, and seems to have embarked on his plan to “befriend” Symond Templeton, but the resulting public show demonstrated that this was a marriage both sanctioned by the current ruling power of the Vale and accepted by key representatives of the old Vale nobility. That open aristocratic approval might in turn go some way (though only some) to cutting prejudice against Lyonel’s future children, in a way Gawen and Sybell did not enjoy. (Naturally, though, Lyn Corbray, the most immediately injured by Lyonel’s marriage - since he’s about to lose his place as heir presumptive to Heart’s Home - disdainfully refers to his sister-in-law as a “peddler’s daughter”.)