Why does my friend want whatever I have?

[Anonymous]

Every guy I date or job or dream that I want, she suddenly wants as well. She competes with me for them behind my back even if she didn't want them before.

I got a new job and she tried to discourage me from interviewing, but after I got hired tried to sabotage my position and get the position instead of me. I am now dating a new guy and she wants to date him as well even though she's already with someone. Why?

[Berethor]

Girls can be silly, as a guy I don't want a sloppy seconds.

[Changiis07]

She isn't your friend then