My two cents; never give up until you are really ready to give up.
If you want passion in your marriage fight for it, tell your husband that it is important to you. I can understand discouragement. To me, GAL is more than just loosing weight or developing a new hobby, it is about giving you new skills and new confidence and showing both you and your spouse that change is possible.
MWD's approaches to saving a marriage and dealing with a sex starved marriage sometimes, but not always will work. Still they are a really good approach. GAL is a cornerstone of may of her recommendations.
As to venting, please do, as it is what helped me through a very dark time in my marriage. Based on your comments about not feeling sexy, there is a really interesting book that you might want to read. It is based on interviews with literally thousands of women over age 50 and was focused on their sexuality and sensuality and the things they did to keep themselves happy. It is called still sexy after all these years.
Good luck
>43 years of marriage--My wife and I are now closer than we have been in decades. I believe that my SSM is over.