How would you handle a situation like this? Curious if this is black and white thinking?

I’m wondering my thinking is too extreme, but I have a very low tolerance, essentially nonexistent, for being treated like second-best. As in, knowing I was only chosen because someone else was picked first and said no. For example: if you were really into a man and then found out he’d asked your close friend to marry him first, but she turned him down, wouldn’t that kill any feelings that you have? I mean immediately? Same for friendships.