He's friends with her because 'he's not a jerk.' But like why I am told this story?

Because his self-esteem took a hit when she friendzoned him (“assumed she didn’t like his looks”). He knows you think he’s attractive and want to spend time with him. If he was interested in you, he’d be initiating some dates and not telling you about another woman he wants to get with.

He’s still friends with her, not because he’s a jerk, but because he’s hoping she’ll change her mind to date him. He’s hanging out with you because he is a jerk & using you for ego validation. (It’s extremely jerky behavior to tell a woman you know is attracted to you and you go on dates with about the woman your really want)