What questions do you ask people who use your app everyday?

We're a new app that launched 1 week ago and we've noticed some people who downloaded our app from the start and are using it consistently everyday for more than 1 minute (not sure how long altogether) and share it on social media without us prompting, we're going to interview a couple who agreed to meet us and was wondering what good questions to ask which won't seem weird.

Thanks, for better context we're a dating app. I know theres some stigma around dating apps and that we're in a competitive space.