It's true that losing weight is about 80% diet and 20% exercise. This means you should be able to start losing the excess weight by eating more healthily.
But, once you've lost the weight, maintaining it does rely on exercise. People tend to eat quite restrictively when losing weight as it becomes quite rewarding to see the scales change and the inches go. Then you reach goal weight and the restrictive diet becomes harder and harder. Old habits die hard and there's a reason more people regain the weight than keep it off. This is one very good reason why exercise is good because exercise tends to keep the weight off.
Exercise will also help with your health, well being, positivity, mental health, motivation, energy levels, sleep etc.
Everybody can fit exercise in. Whether it's getting up earlier and fitting in a short DVD, doing a DVD in an evening, going to a gym in an evening or at weekends, cycling to work, parking further from work and jogging in, using your lunch break, taking up a new hobby, walking, swimming, dancing, climbing, hiking, chasing the dc round a park/pool/forest. The possibilities are endless.
Is there any exercise you particularly fancy?