Howie I think you have mastered emotional fluctuation. You have learned to lead and you're nobody's fool and not a chump. So from a frame & inner game place I trust that you are good.
When a woman like this (one used to having the upper hand otherwise known as bossing the frame) runs into a real man, a man's man, it brings to the surface all the stuff that you (as a chick) have never had to deal with in yourself because you were used to rigging the game (best way I can explain it). You're used to getting your way as a hot woman and you aren't required to be your personal best.
Maybe such a woman naturally has solid character and high standards for herself but she isn't used to being led nor held to account.
All of us will conserve energy if we can. Facing inner crap in ones self is an uncomfortable place and it requires energy. So we all tend to resist it. Until we run into someone who requires MORE as a matter of course.
The fact that you hold the frame increases your value in her eyes Howie. And she sees the increase in value as relative to her value. This means she is invested and she has something to lose. And that makes a girl nervous, especially if she's not really been in that spot before.
To be frank I find myself in a similar situation. I'm more off balance in my LTR than I like...and I swear my guy likes it that way ever so slightly, lol. I don't suffer from anxiety per se...but that man occupies a bit of headspace, in case my comments around the board aren't obvious in that regard.
I would suggest 2 things which I have found helpful. One is solid and direct communication (by that I mean a willingness to discuss her "stuff" and how it relates to your "stuff" and how it shades the dynamic of the relationship), and be both unvarnished but gentle in the exchange, and Two is transparency and building of comfort.
Comfort within the relationship is critical for both of you to relax and relate to one another. It is not "beta" or weak to provide reassurance & comfort. Rather a real man provides that from a place of strength.
Sometimes she's going to be hormonal, she's going to have a high strung moment here & there (ask me how I know, lol), but if she knows she can come to you with those things and find you steady & stable it will help calm her mind. If she's spinning off in 60 different directions, give her a hug. Tell her your going to hug her and do so in a secure way, a supporting way. Bring her physically in and protect her.
Hold her until you feel her relax into your arms (Google Hugging until Relaxed). It helps I assure you.
Don't assume this is insurmountable. You might both need a few different tools in the toolbox.
Wish you all the best - BE