Talking to my cousins ex

So I was on bumble when I saw someone I knew and realized it was my cousins ex, we matched and we began talking. I then stated I think you dated my cousin and well he did. We have met before (at least I know he’s not fake) and he’s very sweet. My cousin was the one that broke it off and never spoke to him since. How wrong is this? I’m 19 about to be 20 and he’s 23 and just graduated college. I’m scared to mention anything to her because it is my close cousin. He’s asking to hangout on Wednesday and I just really don’t know if I should continue this or not..