Can any of you guys explain this female behavior to me

[Aceofspades404]

ok so I'm confused about something. There is this girl who "claims" to be so happy in her relationship and how her boyfriend is her God sent, yet she's jealous of me b/c a guy who is not her boyfriend likes me.
I seriously don't get it. And she will sit there and talk bad about me to her boyfriend b/c of the whole thing and make up lies about me and how I'm a hoe.
Is this guy really that stupid that he can't gauge his own girl's character?
Like is she just being a petty female or is it deeper than that?

 

[YaBoy]

Women don't even understand women we have no hope

 

[The5thLetter]

Why is she minding your vagina? She's salty that he wants you and not her, and her man is too much of a simp to peep game. Any man that would even entertain that petty gossip is a bytch to me, no wonder she wants that other guy.