Jusr curious about different opinions on the matter.
Most Helpful Guy
Yeah I think it is but it is not as black and white as that - First look at the dynamic between him and her, if it is obvious that he does not have feelings for her and likes you more. If you like him then maybe ask her permission to pursue it but if you are both on a equal footing I am afraid it is whoever liked him first, don't cut across her, if she tries and is turned down politely (if he rejects or uses her badly, don't go there) then maybe think about giving it a go.
Only applies for crushes, different dynamic with exes.2