Thanks for your reply Ciel,
She is holding back emotionally. She is protecting herself from me because of the pain I caused her 7 years ago by falling in love with someone else (which at the time we were in a mono marriage), and then the pain she feels because of my ongoing pain and sadness. So because she is protecting herself from me, she can't open herself up fully to me, which she admits. But because I'm still in pain, particularly when I see her not opening up to me, but I see how she does to her new man, this ongoing pain causes her to keep the protective walls up, which keeps me being confronted with the very thing that is causing me pain.
I hope this makes sense...