I'm 45, I've been overweight for 40 of those years. Maybe I should just live with it, I'm not sure I have enough willpower to do much about it any more. There are more important things in life!
Being a health psych, my sense is that your experience is entirely normal - successful weightloss is so rarely maintained, there's a database of people who kept the weight off. I get money from research councils to develop and evaluate interventions to promote weight loss because UK people are cheaper when they are skinnier. Whether you should live with it is your choice - there's a chance you'll experience less morbidity, but that the benefits of a lower BMI are less than you think. Even still, probably will be cheaper for society.
What's interesting to me is the willpower thing. My PhD was in the area of models of motivation and their ability to account for intervention induced behaviour change in the context of obesity protective behaviour. In plain english (or as plain as I can do), my PhD looked at whether when exposed to efforts to change diet or exercise, is it individual's motivation that makes the difference. The answer from my studies was "mostly no". My mate Tom, who also is an audaxer, did a landmark meta-analysis that showed that across all behaviours, it takes a huge change in motivation to bring about a little change in behaviour.
TL:DR - don't rely on will power. Change your environment so that good habits* are sustained by default, and self-monitor rather than put your head in the sand.
*what those good habits are is beyond my expertise, but the results from that database are...
45% of registry participants lost the weight on their own and the other 55% lost weight with the help of some type of program.
98% of Registry participants report that they modified their food intake in some way to lose weight.
94% increased their physical activity, with the most frequently reported form of activity being walking.
There is variety in how NWCR members keep the weight off. Most report continuing to maintain a low calorie, low fat diet and doing high levels of activity.
78% eat breakfast every day.
75% weigh themselves at least once a week.
62% watch less than 10 hours of TV per week.
90% exercise, on average, about 1 hour per day.