Time goes by, and the body takes a toll. Not saying it's impossible, but just to account for the time factor when defining goals so to make them realistically attainable and not have to deal with the psychological issues of "trying very hard and not seeing results".
Life happens, twists and changes and sometimes brings things that are not necessarily desired. With the right attitude (your attitude), and simple action plans, things can change for the better.
I hear you about how impractical it is to cook for one person when there's only two at home. Ever explored the vegetarian world (beyond what you see your wife eating everyday)? There are a lot of new cooking techniques and recipes that make vegetarian version of old time "meat classics" and the results are actually not bad. Perhaps that could be an interesting exploring exercise that you can enjoy together. You wont jump with both feet into becoming a full time veg., but just having a few meals/week replaced by the veggie version may help with weight loss in the long run.
Good luck