I would forward her a copy of this post... It seems to me that you are a very grounded, non-threatening individual who is comfortable and secure in your relationship. I cannot see why she would be so hesitant or worried about bringing this forth unless she is not giving you the while story.
For what it's worth try giving her a little extra reassurance (it sounds like she needs it) and possibly promote this friendship if that is OK with you.
All the best
"Wovon man nicht sprechen, darüber muss man schweigen." -Ludwig Wittgenstein
Me- Linkin Park- the husband. I am the youngest, fast paced and admittedly full of issues.
Nina Simone- our wife- slow, gritty, and sexy like a smoky piano bar and a glass of brandy.
Led Zepplin- our wife - a rocker little tomboy that loves with everything. All she's got or nothing at all.