Well, if you really want to know . . . ask her why.
When she tries to play it off (and she probably will) calmly insist that she tell you why.
And if you're genuinely fed up with the tension between her public portrayal of your marriage and the private reality, tell her so. Tell her you can't accept it anymore. Tell her the marriage she potrays in public sounds wonderful and you'd rather be in that one. Tell her you want to make that one and you want her to help you. And tell her that if you aren't able to make a a real, loving marriage with her then you'll end the marriage. This will only work if you really mean it, of course. Only you know that.
This probably sounds scary, and it is, but it's the only thing I've found that works.
