Sleeping with your best friend ex?

Nicole
Ok 'old situation' just like some insight 
My area is small. Here are the facts.
I met a guy 
We talked for a while 
Getting to know each other on a deeper level 
This is going on two months 
We're sitting in the car talking one night looking at each others social media 
I show him my best friend 
He gives me the craziest look ! 
Hes like I know her 
From long ago 
Im like oh thats my homie talking her up and such 
I meet up with my best friend 
She telling me about her guy im telling her about mine 
We planning double dates and all. 
I show her PIC she look at me crazy like 
Oh I used to fuck him in "middle school"
At this time we 21 years old 
OK.... I'm lost 
So then it turns into this back and forth combative issue her vs him I'm in the middle getting two different stories 
Then they have a conversation behind my back all of a sudden I'm the bad guy and all this he say she say turn into Alexis said ! Omg ! Let's just say I lost my best friend and potential boyfriend 
Was I wrong to continue to try to pursue a relationship with him although he and my best friend were together 10yrs prior? Also considering I didn't find out about them until two months in like tell me !!! lol it was crazy 
There's an update to this if anyone cares 

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