Good point about JA using Ryan as her alibi... But I think your understanding of an "insecure" woman is too literal.
What the other commenter meant was that Jodi was "emotionally" insecure. She readily admitted that in one of her interviews...
A woman's who's insecure in her relationship(s) lacks confidence about her ability to keep a man interested. As a result, she acts irrationally, in constant fear of losing him. These women drive a man crazy with their hysterics, constant questioning, trying to trap him in a lie, getting angry about how he smiled at their waitress, and so on.
EVERY woman is a threat in her mind. The man cannot enjoy peace with her for long, because every other day, she's accusing him of cheating.
She finally has her sexy, career-focused "prize" or "hero" and always worries that a better woman will come snatch him away. Because deep down, an insecure woman feels she isn't pretty enough, smart enough, personable enough, from an important enough family, doesn't have her financial act together, etc. etc.
So she's paranoid, jealous, possessive... eaten away by fear of being abandoned by the one person who put a smile in her heart... or awakens her soul and libido.
And yes, she is so irrational that she will drive hours away all alone... to put an end to his attempt to abandon her.