Is there any adaptation where SWK does stay happy with his love interest?
There is surprisingly not a LACK of SOs that do end up with a Wukong but just that you have to be willing to accept it as "Wukong" so to speak.
But otherwise, it is very rare that there is a universe Wukong ends up with a love interest… mostly cause a lot of adaptations are based in the middle of the journey, they are Retellings, hence the return to the status quo is only to be expected, or that it is afterward, where Wukong becomes Victorious Fighting Buddha.
In most circumstances, adaptions that would have Wukong with an SO and have the circumstances where they are able to get together are without a doubt going to be more Alternative Universes where the setting is completely different or Appropriations where they are more character-inspired than anything else.
Trying to make a list of Every Significant Other that DIES (this list is only for Wukong, not Sanzang, Bajie, or Wujing though those exist as well)
Green - Retelling
Blue - Continuation
Purple - Alternative Unierse
Pink - Appropriation
A Chinese Odyssey Part Two: Cinderella (1995) 西遊記大結局之仙履奇緣 - candle stick lady dies but comes back to life, but they def don't get together
Journey to the West (1996) 西游记 西遊記 - Wukong not interested in spider girl but she still uncultivated back to spider
My Son Goku (2003) ぼくの孫悟空 - remake of Tezuka's Alakazam the Great, Rinrin dies in this one.
Spring Brightened Zhu Jiumei (2011) 春光 灿烂 猪 九妹 - all a dream Wukong gets with femme Bajie
The Grow (2012) 金箍棒传奇 - Wukong's staff turns into a woman and back to a staff
Monkey King (2014) 西游記之大鬧天宮 - lady fox dies by DBK
The Monkey and the Banshee (2016) 猴王与女妖 - White bone demon dies of broken heart cause of Wukong
Taste of Love (2015) 紫霞 - Chinese Odyssey clone
Immortal Demon Slayer (2017) 悟空传 - woman dies by Queen mother
Monkey King and Million - Journey to the West Sidestory 6: Fall in Love with Monkey King (2017) 西游外传之爱上美猴王 - jade rabbit falls for him and dies I think?
The Legend of Sun Wukong (2017) 悟空前传 - Chinese Odyssey clone
A Chinese Odyssey: Million Years (2017) 大话西游之爱你一万年 -Chinese Odessey clone
Winning Buddha (2017) 斗战胜佛 - reincarnated into the next life, his crush dies so he can become Wukong again
Journey to the West: Rediscovering the Power of God (2017) 西游记之再显神威 - Wukong and Iron Fan are reincarnated in the next life and get together, so they technically did die
Monkey King and Million Demons City (2018) 齐天大圣·万妖之城 - I'm pretty sure that flower demon dies
Till We Meet Again (2018) 千年来说对不起之 - flower girl dies in the story, meet in the next life
The Monkey King: The True Sun Wukong (2019) 美猴王之真假孙悟空 - dragon girl dies and turns into the Ruyi Staff
Monkey King - The Volcano (2019) 齐天大圣火焰山 - flame spirit girl BECOMES HIS FIERY EYES
The Westward Movie (2020) 西行纪之再见悟空 - killed by her own father, the Jade Emporer
Great God Monkey (2020) 大神猴 - princess of all demons falls for him and dies
Tears of No Regret (2020) 斗战胜佛之大圣之泪 - fallen star woman that keeps messing up her life
The Monkey Is Back (2020) 混世四猴:神猴归来 - Dude.... he just not into you~ but yeah random woman dies but I think she comes back to life
God Of High School (2020) 갓 오브 하이스쿨 - Femme Sanzang and Wukong but she dies and he has to eat her to defeat big bad
The Regrets of Journey to the West (2021) 大话西游之遗憾 - another dead dragon girl
A Chinese Odyssey 1 (2022) 大话西游:至尊宝 - Chinese Odessey clone
A Chinese Odyssey - Origin (2022) 大话西游之缘起 - Chinese Odessey clone
Legend of Wukong (2022) 悟空传 - Immortal Demon Slayer clone
Journey to the West: Marble Mountains (2022) 大梦西游之五行山 - demon hunter dies and Wukong is placed under the mountain
Wukong (2022) 悟空传 - Chinese Odessey clone
Punishing Son Goku (1954) 殴り込み孫悟空 woman falls in love with Wukong but he wasn't interested in her... so maybe that why she lives
Alakazam the Great (1960) 西遊記 - lives and he married a monkey girl Rinrin
SF Saiyuki Starzinger Movie Edition SF (1979) 西游记 剧场版 SF西遊記 スタージンガー - Femme Sanzang and Wukong in scifi universe
Dragon Ball (1986)ドラゴンボール - Goku "Wukong" gets married to Chichi "Iron Fan"
Monkey Magic (1998) モンキーマジック- femme monkey lives but they don't get together
Shinzo (2000) 爆裂战士マシュランボー - Wukong and femme Sanzang marry
Journey to the East (2002) 都市东游记 - Wukong and femme Sanzang get together
RWBY (2013) 红白黑黄 - Sun Wukong's SO lives but does not end up with him
Miraculous Tales of Ladybug and Cat Noir (2015) Miraculous, les aventures de Ladybug et Chat Noir - Wukong inspired character has a girlfriend
A Chinese Odyssey Part Three (2016) 大话西游3 - ret-con of previous movies to have Six Ears go on journey and Joker never becomes Wukong to stay with Zixia
A Korean Odyssey (2017) 화유기 - Wukong and femme Sanzang end game
Dream Journey 2 Princess Iron Fan (2017) 大梦西游2铁扇公主 - Wukong loses his memory and becomes someone else, falls for Princess Iron Fan, but gets his memories back later
New Journey to the West: Unexpected Jingxi (2017) 新西游之意外晶喜 - accidentally knocks up White Bone Demon but he aint sure the baby is his
Journey to the West The Legend of the Merman (2017) 西游鲛人传 - gets with a mermaid after the journey
The Monkey King’s Daughter (2018) 猴王的女儿 - gets with Gaunyin's daughter I think?
The New Legends of Monkey (2018) 新猴王传奇 - Wukong and femme Sanzang end game
Three Eyes Broken Sky (2019) 三眼哮天录 - more of an Erlang Shen reborn as a girl and Wukong hits on her
Ultimate Westward Journey (2019) 终极西游 - Wukong falls for femme Sanzag in the next life
The Legends of Changing Destiny (2023) 凌云志 - Wukong and Sansheng Mu get together ??? not sure
This is all the one that I am AWARE of at the moment but as you can see a lot more Retellings/Continuations are where Wukong's SO dies and this is mostly for the case of keeping the status quo and moving on with the original plot. They are more like additions of the OG story that let Wukong have his character moment.
It is far more with Alternatives Universes or with other Continuations that there are more 'alive at least' SOs, some in the case of reincarnation or being in a different setting for the plot otherwise. Some of them don't even end up WITH WUKONG (most likely save their lives).
Just depends on what you are watching but traditionally Wukong does not have alive SOs for the sake of the plot/character development, while in other he has them alive where he is less Sun Wukong or is it taken out of the xiyouji context.
If you have any more please let me know cause a lot of plot summaries just DONT include any mention of a romance subplot. I can only imagine WHY.