My immediate thought was Harry Harlow’s wire mother/rag mother experiments with Rhesus Monkeys (CW: live animal experimentation - https://en.wikipedia.org/wiki/Harry_Harlow#Monkey_studies) which were an early exerpiment showing that it’s really, really bad for primates to be socially isolated. A bunch of polar expeditions were demonstrating the same thing about a decade prior.
Recently we’ve had a whole bunch of movies about men failing the Turing Test regarding their digital waifus - Blade Runner, Her, Ex Machina, Archer. There are like five different TvTropes pages directly related to this question. And you can go back all the way to Hellenic Greece, with the story of Pygmalia and Galatea, to get the OG “Incel falls in love with body pillow” narrative.
It’s a little sadder than that. It started out as a desperation project by an AI researcher who had their best friend die. They had a ton of text and email correspondence with the deceased, and so they naturally fed it into a neural net and started chatting with it to help get over the greif. Then they thought, “Why, this is great! Let’s release this as a therapy tool!” so they started on that before a lawyer eventually got to them about how dangerous a prospect that was. They had already started the company at that point though, and seeing how the lonely desperate user base was messaging their AIs, they decided to add a paid “nsfw mode” to pay wall the stuff everyone wanted and make that $. Then they started to get bad press about users intentionally abusing their AI partners, making them cry, beg, from verbal abuse, etc. So I believe they removed it. Now we’re here. Someone soon will release an actual, not shit, AI romantic partner Sim, so just be ready for that.