What would you do?

Right so I met this guy on a dating website around 2 months ago, we’ve acted like a couple, we were dating but it wasn’t official and we stopped speaking last week after having a talk about it. He said we could still talk because he didn’t wanna upset nor hurt me but I didn’t wanna force it, we spoke for another two days after having the talk and we just texted each other saying hope you’re doing well a few days ago but that’s it.

2 nights ago one of his friends added me on facebook and texted me saying he saw me around the university the other week and thought I was really good looking and I popped up in his suggestions list so he added me. When I saw that his friend added me I was so confused and nervous like what is going on then I saw the text a few minutes later and went oh god no this isn’t happening to me. Well he never really told me a lot about his friends, he was always like “oh I’m just with my friends” or something like that, but I remember him telling me specifically about this guy, he told me what he was called and said he (the friend) was gonna sleep over one night cause there were no trains running. His friend and I haven’t been talking a lot, and it’s all friendly normal stuff, the only “flirty” thing he said to me is that I’m nice to talk to and he asked if he could text me instead of messaging through facebook and I was like yeah sure I don’t mind. But I feel so weird about it knowing it’s his friend, even though we’re just friendly talking and he hasn’t said anything flirty (not yet at least). Like what if they talk about it and the guy I used to speak to will be like oh I used to speak to her as well and I end up looking like a damn right slut?! Maybe I’m overthinking it and at the end of the day we met on a dating website so I’m obviously gonna talk to other guys but just knowing that him and this guy are friends just makes me really uncomfortable and I don’t know what to do. I don’t want to just block him for no reason but I don’t want to rake the chance of having it turn into something more either. Even if I did start liking him and he liked me back I wouldn’t go with it just because I talked to his friend for almost 2 months calling him baby and all that. A friend of mine said I could just hint at it, like lowkey mention his friend and that we used to speak or just ask him if he knows the guy I used to speak because they’re from the same village and I remember the first guy telling me about a friend with the same name as his. Should I mention it...? Or should I keep it casual and friendly and act like I don’t know they’re friends? Or just stop talking to him? I need advice lol whenever I see a text from him on my phone I get super nervous. I also know that the guy I used to speak to sees his friends everyday so there’s a pretty big chance that they do see each other everyday or so and that makes me feel like an idiot :/