He could also still be using dating apps, because – as great as you are – he doesnt quite know what he wants. Maybe he hasnt been single that long, maybe he isnt ready to settle down or maybe hes speaking to others to see if there is any interest there or if hes 100% into you.

Should I ask him if he is still on tinder?

Also, do you know they are still on Tinder because a friend of yours saw them or because you saw them with your account? It isnt really fair to ask someone why they are still on the app that you are also still using. In the end, you have two options. Talk to them and clear things up.