Search Results: guys with girlfriends still flirting

On Insta you always get people recommend and all that, there was a Guy I used to be friends with, so that's why this question haha

Like that friendship didn't worked out, he gained feelings, long story, never talked with him again

But I do believe friendship is possible and I do have in my surrounding two close friends where it works great

I believe that if both sides make it clear that there is nothing and will be nothing, it can work.
Or like if there is no sexual attraction.
I also read somewhere like physical attraction is also critical , but like both are good looking, one is a 8 and the other one a 9.5, like I'm not blind haha but still like I'm not attracted to them at all and thankfully they feel the same, one does even have a girlfriend, so I feel like sexual attraction is more important.
But learning from mistakes, I don't talk with them about my problems that much and no flirting with them or it does get weird haha

Anyway what do you all think about this topic?
Curious to hear other opinions