Weight gain cronicals

So I've been with my wife for 11 years, and over the years I've gained weight and got comfortable with it. I must say I gained around 20-25 pounds. Now it's noticeable. My wife n I aren't having so much sex anymore either. She said something today that really hurt my feelings... "Then u wonder why were not having sex, go to the gym. The average women does something to change!" I cried.... she apologized but yet I now know how she sees me. What should I do about it?