1. Tinder

Tinder is one of the most popular dating apps out there. If your partner is in a committed relationship, there’s really no reason for them to have this app on their phone.

With its system of creating matches by mutually swiping right on someone’s profile picture, Tinder is designed for dating – not long-term commitments.

2. Ashley Madison

This is a pretty big red flag when it comes to infidelity.

Ashley Madison is specifically designed to facilitate discreet affairs. It even encourages married users to look for a little excitement outside their marriage.

3. OkCupid/Bumble/POF (Plenty of Fish)/Grindr

These apps work in a similar way by matching users based on mutual profile likes.

Like Tinder, they are location-based and suggest potential matches within a certain proximity.

In particular, Grindr operates similarly but focuses on the LGBTQ+ community, being the largest social networking app for gay, bi, trans, and queer users.

4. Line/Viber/Kik

We all use instant messaging apps like WhatsApp, Telegram, and Signal, but it’s the lesser-known apps where secrets might be kept.

Apps like Line, Viber, and Kik offer end-to-end encryption and extra privacy, making them attractive for secret conversations.

While having these apps doesn’t necessarily mean anything shady, it’s curious if your partner uses them and not for chatting with you.

Remember, even if they don’t have one of these, that doesn’t mean they’re not using more common apps like Facebook Messenger, Instagram, or Twitter for secret communications.

5. Vaulty Stocks / Private Message Box / Avira Vault

These apps are designed to be more hidden on a smartphone.

They can hide not only messages but also photos and videos.

Using these types of apps, people can communicate privately and store content away from prying eyes.

While their presence alone doesn’t confirm an affair, they can raise suspicions.