Should i date someone my ex hates?

Im not trying to be petty but my ex hates this guy, they've never got on at all. i knew him before i knew my ex and we did stuff, then he went away with his work n i met my ex, not knowing they knew each other (i mean they weren't fb friends or anything) then when this guy came back he was flirting with me like usual and i explained I was with my ex and he said sorry and left me alone but my ex saw it and claimed he was doing it deliberately coz they don't like each other, they used to fight at school and it was his way of getting his own back which I didn't know anything about. 
So I heard through friends this guy went away longterm with work again and while he has been gone we broke up coz it just wasn't working out, we wanted different things so no bad break up or anything. 
So this guy is on tinder, I swiped right and we got chatting, he's coming back home as his job has finished and he wants to take me out properly. 
I don't want no bad vibes with my ex coz its a small town n we still see each other on the way to work and that. 
I don't know what to do? 

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