is it wrong to like your best friends ex boyfriend?

so... my best friend tynna was dating this really cute kid named jaydin and i really like him and he is really nice, sweet,funny,kind and is the coolest guy i know but one day i went up to him and was about to ask him out when tynna walked up of course i said hi and then as i was about to ask the question tynna says "did you know me and jaydin are dating" my heart sunk but i don't if i should tell her i like or not want to ask him out but i don't want to hurt her, should i tell her or not?