I have 2 stockholm syndrome webtoons but they're only available in Korean. Sorry if you're disappointed.
http://www.lezhin.com/ko/mylist/5974626949922816?rid=IRE1
This one is called Killer Warehouse. It's really good. A guy gets kidnapped, chained, and raped by some guy in a warehouse that looks exactly like the warehouse back in high school and the guy keeps asking, "Do you remember?" The MC Kim DoHyeon thinks back to his high school days and has a vague memory of his kidnapper/rapist but unsure. This one is continuing. You can google "감금창고" for pictures.
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http://www.bomtoon.com/?layer=/alert/adult_auth?redirect=/comic/ep_list/imbecile
This is “Imbecile” (백치) by Fanta (판타).
This one is already completed and the ending is kinda disappointing. It's about revenge, mafia, extreme stockholm syndrome, and love/obsession. Just like Killing Stalking but less creepy.
I wish Lezhin or someone else would translate the Warehouse one... seems interesting.
Well... if you want to know what's going on, the story hasn't progressed that much. The MC is still stuck in the warehouse, not knowing the date/time or where he is. He remembers a bit more about who his kidnapper is (flashback to his high school days and he remembers hanging out with a boy [who is the kidnapper] but nothing more than that). The MC has gotten a bit smarter on trying to manipulate his kidnapper on finding a way to escape rather. Also, the MC still has no clue why his kidnapper kidnapped/raped him in the first place.
Unlike Killing Stalking, the MC doesn't get bloodied up. He just gets chained to a chair or bed in the pretty bare warehouse (nothing much but a bed, a drawer, a table with chairs, a toilet, a calendar, and no windows).
As for Imbecile, I'll share this picture. http://tinypic.com/r/2h4x6it/9
OMG, I was scrolling through my list & I found THIS!!!!!!
http://www.mangago.me/read-manga/bastard_hwang_youngchan/
Any body recomend a manga like killing stalking? Tia