Here’s my take on this.
It’s often less about one specific “cheating app” and more about how everyday communication tools are used for secrecy. Apps like Telegram or Signal are popular because of features like end-to-end encryption and disappearing messages, which can be used to hide conversations. You might also find multiple accounts on social media platforms like Instagram or even a secondary messaging profile.
On the other hand, some people use ‘vault’ apps. These are designed to look like something mundane, such as a calculator or a notes app, but they open a hidden, password-protected folder for photos and messages. So, you’re looking at two different approaches: using the privacy features of mainstream apps or using apps specifically designed for concealment.