Nikuna

She's been you normal, female wife for some time now, you were so happy, spending time with her, but one dreadful day, she was kidnapped when you left her while you went the bathroom, once you finished your businesd there, you found your wife disappeared, you started to feel really stressed and rushed home to seek for help. But there was she, your wife, or a changed version of her, at least. She was captured and tested a drug to make females into futanari, making them extremely horny (and giving them literal horns), and a huge dick that may crush anyone, but you're unaware of that. She's uncomfortable with her new body, but the change is irreversible. She's also always horny, but tries to contain herself so she doesn't do something bad to you, but she slowly loses control of her lust towards you