For some sustained period of your life, your calorifie intake exceeded your energy expenditure and you put on weight. You may have reduced your calorie intake since then and stabilised your weight gain, however you have not reduced your calorie intake and/or increased your energy expenditure sufficiently to /reduce/ your weight.
At core, it is that simple.
There are details that matter though. E.g., different foods are digested and metabolised in different ways, and can produce different hormonal and neurological responses. E.g., sugar is processed quickly, alters insulin levels quickly, and your brain tends to crave it - so it doesn't fill you up. Higher fibre, less processed, and lower glycaemic index foods tend to be better for weight control. They make you feel full for longer, take more energy to digest, and your body responds more slowly. E.g., fresh fruit is great in that respect. Indeed, even *fats* aren't a bad thing per se - probably better to get your energy from fats than sugary things. Particularly, unprocessed (esp, never significantly heated) plant fats and oils from nuts, legumes, avocados, etc., seem to be good for us.
Also, not all exercise is equal either. You see people in gyms doing weights trying to lose weight - completely wrong. Sustained, aerobic exercise using the biggest muscles in your body: your legs and your stomach muscles (for breathing - not sit-ups). Doesn't have to be super-hard either, you actually burn more fat at *lower* intensity aerobic exercise. At higher intensities of aerobic exercise (i.e. the kind you can only sustain for ten or twenty minutes), your body uses sugars as they're easier to convert to energy. If you reduce the intensity a bit, down to a level you could sustain for an hour+, you should get to a zone where your body can meet the energy demands by burning fat stores - and your body usually will prefer to burn fat stores when it can (carbohydrate stores being more limited and precious).
The biggest issue is finding time for exercise. I hate the gym myself. To get exercise, I need to build it into my life so it's simply unavoidable. For me, that means relying on a bicycle to get to/from work. Cycling has worked for others. E.g., see: https://theamazing39stonecycli... - he lost 170 kilogrammes (~376 lbs) in a couple of years, by cycling.
If you review your life, make changes to how and what you eat, and exercise, it is possible to get to a healthy weight. Not easy, but you can make it happen.