Matched someone I knew previously on Bumble..

So, a couple of days ago I matched someone I knew from church a couple of years ago on Bumble and we’ve been messaging back and forth since. The only problem is that I know his ex girlfriend and used to be friends with her. Not great friends, more just like situational, at church friends, but friends nonetheless. I don’t know if anything is even going to develop between him and I, but I do feel kind of bad because I’m talking to him and they dated for a couple of years. I still have her on some social media too. I mean I always thought he was cute but they were together and everyone, including me, really thought they’d end up getting married one day. I’m not sure when they broke up, or why, but I guess I’m just wondering if I should mention something to her? It’s been a couple of years since we even talked, but I feel like I should say something. Or do I just wait it out and see what comes of he and I talking and if it progresses into something more tell her? Or do I even need to say anything at all?