Fwb slept with my friend

So I’ve got fwb kind of situation with this guy who lives an hour away from me. today at work I was talking to a close friend about him. I mentioned that he was good looking so she asked for a photo and I showed her and she started laughing and was like “omg I can’t believe it I was hooking up with him a couple of years ago” I felt so weird about it she just found it super funny but I feel so strange about it. Like it was a while back but still she said they met on tinder and him and I met on Bumble

I don’t know whether it’s worth telling him Or not because I feel like I can’t grt passed it without telling him. I know it won’t make a difference it’s just someone he has slept with but the fact it’s someone I know makes me feel uncomfortable and she told me his clingy and a “hoe”.