Stendyle or Stylendy is the name given to the romantic polyamorous coupling consisting of major characters Stan Marsh, Wendy Testaburger and Kyle Broflovski. The names Stendyle and Stylendy both incorporate the names of the third character in the relationship into the existing ship names of Stendy and Style respectively.
While not explicitly indicated, Stendyle is fairly distinctly implied through the fact Stan is canonically romantically attracted to and has dated Wendy and is implicitly attracted to Kyle, whilst Kyle and Wendy have noticeably similar character traits (such as a dislike of Cartman, being fairly headstrong, and a tendency towards liberal political and social activism).
Furthermore, they have been seen to get involved with each other on numerous occasions. In ‘Cartman Gets An Anal Probe’, while ostensibly on a date with Stan, Wendy helps Stan and Kyle use Cartman to draw down the aliens to try and save Ike.
In ‘Weight Gain 4000’, the three of them cooperated to prevent Mr Garrison from killing Cathy Lee Gifford, and after the end of the parade, they went back to Stan’s house for tuna sandwiches.
One of Wendy’s memories of her and Stan in the montage in ‘Tom’s Rhinoplasty’ sees Stan and Kyle riding the elephants when Wendy approaches them and attempts to talk; although at first glance it would be assumed she was just talking to Stan, since their dialogue is not heard, it is possible she was addressing both of them. Furthermore, although Kyle is shocked by learning what Wendy did to Miss Ellen at the end of the episode, he never revealed this to Stan and only lightly chastised Wendy; this might imply it does not overrule his feelings towards her.
At the end of the flashback to ‘Cartman Gets An Anal Probe’ in ‘City On The Edge Of Forever/ Flashbacks’, Stan imagines that he went up to Wendy and kissed her while Kyle watched them, smiling. This could indicate that Stan would’ve liked Kyle to be present to see him and Wendy bonding during the ending of that episode, which he was not.
During ‘Chef’s Chocolate Salty Balls’, Stan is simultaneously put in the position of helping Kyle save Mr Hankey and going to see numerous homoerotic movies with Wendy, and the three are seen together at the very end of the episode. One could argue Wendy was trying to encourage Stan to appreciate gay media more and destigmatise the idea of being in a poly relationship.
Although the plot of ‘Clubhouses’ revolves around Wendy trying to convince Stan to help her hook up Kyle with Bebe, providing the basis for the Kybe pairing, that Stan is duped into reading a note praising Kyle’s ass and Bebe’s eventual ‘breakup’ with Kyle indicates that Wendy may not have cared so much about hooking Kyle up as getting him to spend time with her and Stan in a romantic setting.
When Wendy auditions in ‘Something You Can Do With Your Finger’, Stan and Kyle enthusiastically cheer her on and (along with Kenny) convince Cartman to let her join Fingerbang. Additionally, at numerous points the three of them can be seen sitting together.
The three of them appear as co-actors (with Stan and Wendy playing Helen’s parents) in ‘Helen Keller: The Musical’.
At the end of ‘Proper Condom Use’, at the very end, the three of them can be seen in a group hug behind Cartman as he red rockets a dog.
A subtle example can be seen in ‘South Park Is Gay!’, when after having Kyle undergo a metrosexual makeover, Stan says he’s excited to see what Wendy thinks of them. This could imply he wanted to get her input on how he and Kyle could improve their metro fashion approach.
One of the episodes which most heavily implies Stendyle is ‘Follow That Egg’. Kyle and Wendy are paired up to look after an egg, and Stan, dejected at not being paired up with Wendy again, is shown to be upset at being excluded from their group. Later on, after being paired up with Kyle to try and prove them to be an irresponsible couple by virtue of being gay, Stan instead becomes highly supportive towards Kyle, and the three of them are briefly seen united at the end, although Stan dismisses Wendy rudely.
‘The List’ is another episode which contains strong implications of Stendyle. Stan is seen to be saddened at Kyle feeling ugly because of the girls voting him last on the list, and gets Wendy’s help to try and have it amended. When Kyle tries to burn down the school out of frustration, Stan and Wendy stop him and reveal the list was a fake and burn the real one as Kyle asserts he doesn’t need the list’s validation to feel beautiful. In addition, in the deleted ending after Stan unsuccessfully tries to kiss Wendy again, Kyle returns to talk to them again.
The episode ‘Super Fun Time’ also sees the three of them cooperate; despite the kids being required to hold hands in pairs, Kyle follows Stan and Wendy consistently throughout their time in the living village. They also work together to try and persuade the village employees to use the assets they have on site to stop the criminals.
In ‘Breast Cancer Show Ever’, Stan and Kyle are both told at the same time that Wendy and Cartman will be fighting after school, and in one of the freeze frames when Wendy lands her last punch in the fight sequence, Stan and Kyle can be seen enthusiastically cheering Wendy on.
In ‘Elementary School Musical’, Kyle appears to be the most inclined to agree with Stan that they should give in to the High School Musical craze, seemingly knowing Stan wants to because of Wendy’s attraction to Brydon just as much as to avoid becoming outcasts at school.
During ‘Butter’s Bottom Bitch’, Butters cites Stan’s experiences with Wendy as evidence his services as a pimp are a good alternative for the boys, to which Kyle is visibly cynical, implying he sees something more to their relationship than Butters.
In ‘You Have 0 Friends’, Kyle and Wendy are both seen to be exasperated by Stan’s inattendence to his Facebook page; Wendy, since he does not list them as in a relationship, and Kyle, because he will not help water his crops frequently, but their reactions towards Stan are distinctly similar.
‘Insecurity’ sees its main plot launched by Kyle and Wendy emotionally implore Stan to get over his hoarding compulsion seen in the overflow of old unnecessary things in his locker.
While the three are never all together during ‘Ass Burgers’, Wendy implores Kyle to help her do something to make Stan feel better, a drunken Stan tells Kyle he loves him (perhaps implying Stan is attracted to both Kyle and Wendy) and Stan and Wendy can be seen picnicking in the ending montage; given that certain members of a coupling being together while their spouse is not can be a feature of polyamorous relationships, this might imply Stendyle sometimes works on the same basis.
In ‘Gluten Free Ebola’, Kyle is proactive in helping Stan find a way to make amends with Wendy (for example through their radio appearance and by investigating the food pyramid), although this may be in part to restore their generally low standing with their classmates.
In the ending of ‘Cock Magic’, Stan and Kyle are seen watching Wendy’s volleyball game together.
In ‘Weiners Out’, Kyle convinced all the boys to attend the girls’ volleyball match to try and make amends with them, and Wendy can be seen waving in his and Stan’s direction, potentially in response to both or either of them. In addition, although later in the episode they both joined in, Stan and Kyle were two of the only boys not to drop their pants to the national anthem.