AIO? My friend was spotted at a bar with my mom.

This happened this past weekend. Neither of them have said anything to me about running into each other. I am concerned they're hooking up behind my back. Am I overthinking this situation? It's very odd to me. My parents separated a year ago, and have no issue with my mom enjoying the single life. Just not with one of my close friends I've know for 10 plus years. This has been bothering me day and night. I've been thinking about confronting them, but keep going back and forth if it's a good idea or not. Any advice?