After reading your other posts, I think there is more going on in terms of your ability to remain attracted to her than just her carrying a few extra pounds...

You're entitled to prefer a particular body type, but if that's what you want, then set her free from the burden of being with someone who feels he needs to "change" her into what he wants, and next time don't compromise on what you want. You aren't doing anyone any favors that way.

I've been in her shoes - I am 5'4" and weighed probably 125 when I first met my ex-husband. He nagged and nagged and I got myself down to 115 by working out like a fiend and completely deprived myself of anything I liked to eat. He still wasn't happy with my body and came up with all kinds of suggestion on changing the way I dressed, getting me a personal trainer to sculpt the "problem" parts, and decided that he just didn't like my body and wouldn't have sex with me for about 2 years - I think we made love maybe 4 times. Eventually he divorced me and one of the reasons he gave me is because he "deserved a thin wife". That absolutely killed me. My best wasn't good enough. My self-esteem was completely in the toilet after 6 years of trying and still failing. Now, 30 pounds heavier (actually, more than that now but I'm pregnant so let's not count that), my current husband loves me to pieces and always lets me know that I am attractive to him. Looking at pictures of myself from back then, I realized that my ex-husband DID have a thin wife! The reality is just that I wasn't what he wanted. I wish he had just told me that instead of breaking down my self-confidence over the course of 6 years. In retrospect, I didn't even look good at 115 - I'm eastern european so on me, the lack of body fat just made me look like a skeleton. Gross.

Just something to think about.