Suspicious?

Boyfriend and I are long distance. We use a video chatting app on occasion. Over the past few months I've noticed that hes been logged in at times when hes not talking to me. Tonight he told me he was going to dinner with his mom. We are in different states but his state has basically shut down restaurants since last month. I havent heard from him since 830 but he was "last seen" on the video chat at 1030. It's now after midnight. Him telling me that hes with his mom isnt unusual, they do usually go out for dinner during the weekends when everything was normal but I'm bothered because I feel like the way this is playing out I'm being lied to. I've never accused him of anything and I've never had a reason to think he would cheat on me but some things lately just have me suspicious of something. How can I ask him, in a non accusatory way, who else he uses this video chatting app with? According to him hes an introvert and doesnt really hang out with people so I feel like it wouldn't be wirh friends.