OP if you eat healthily 85% of the time, the odd treat is fine.
AND it won't harm your kids to push healthier eating on them. Snacks can be cheese, fruit, or plain no sugar yoghurt. TBH no one needs snacks.
I eat breakfast about 7.30 and lunch around 12.30, dinner at 6-7pm. I don't snack in between. if I am starving, my go-to is an oatcake with almond or peanut butter.
Breakfast is usually one poached egg on a slice of mutligrain toast, or greek yog, seeds and berries, or 1 slice toast with nut butter (no sugar) and a sliced banana.
Lunch I tend to have soup (made at home) or a salad with tinned fish (sardines, salmon) or cheese. Apple or other fruit.
It will help if you create a more positive approach to healthy foods.
For example, when I eat a few almonds or almond butter, I remind myself it's got fibre, healthy fats and calcium. One teaspoon takes the edge of any hunger.
Get your fruit and veg up to 8-10 portions a day and you will not feel hungry and you will lose your sweet tooth. I agree with @Aphrathestorm that sugar is addictive. I can't tolerate very sweet things now.
And stop thinking of this as a 'diet' - it's healthy eating, for life! and get your kids to follow your lead? Stop thinking of calories- just eat plain, non sugary foods and loads of lean protein and fruit/ veg, seeds, nuts, dairy and leave out the refined crap.
I recommend signing up for the ZOE newsletters from Prof Tim Spector - go to Join Zoe- and it's full of science about healthy eating. If you want your own personalised analysis of how your body processes food (blood and poo tests included ) and what you should eat for health, you can sign up - it's about £350 but worth thinking about if you have the cash.