<human>: Can you provide a brief rundown of the text in within 3 sentences?

I've been seeing this girl for about 8 months now.  The first six were spent in an open-relationship type situation – I was seeing other women and communicated this from the very beginning.  She said she was ok with it, but she didn't want to hear about it.  She's naturally monogamous but tolerated my dating.

For the past month or so, she's the only woman that I've been intimate with, by choice.  She knows this, and the dynamic of our relationship really changed for the better once she found out that I don't intend to see anyone else.  

But there's still an underlying friction from those first ~7 months.  She gets paranoid when I go out with my friends, and makes comments about me being a playboy or going out with another girl.  It's joking, but it's revealing.  She'll also say things like "don't worry we can cancel, it's ok" if I'm a few minutes late picking her up or meeting up with her.  Or "It's ok, you can go see another girl."  Like she's afraid of being a problem.  

If we don't talk to each other for a couple days, she retreats emotionally.  I have to pull her back out and reassure her that I care about her, and really enjoy her company.  Then everything is golden.  

The need to constantly reassure her is draining though, especially with the ambiguity behind her wants and needs.  I've tried to bring this up a couple times to no avail.  She just dismisses the conversation because I think she's afraid of what she might say.  

So – how would you suggest moving forward?
<bot>: Girlfriend needs constant reassurance.  Without it, she retreats.  How can I work on making her feel secure in this relationship?