Girls, Why does my female friend who rejected me get jealous when I start seeing a new girl?

[Anonymous]

So I told my female friend a while back that I liked her and wanted to date her, she said she doesn't feel the same but wanted to remain friends so I did. Since then, we've remained good friends. Recently I saw a new girl and I mentioned it to my friend. She immediately seemed to change, she's been asking me constantly how it's going with her and her friends have been asking me as well. At one point asking "So, are you going to see that girl tomorrow?" and looks me dead in the eyes. I'm confused at why she is so interested, surely if we were just friends she wouldn't be this invested in who I was seeing?

[bubblegunnn]

Tf ima be confused too if i were u. Like what u want bruh.. i think she got jealous cuz she know u have someone new u like and u will be focus w the new one, and thats make her jealous cuz u won't be focus at her at all cuz well uhave another one to focus at u get me?

[1GoldTwins]

Maybe she's jealous because you're spending less time with her.