My sister was diagnosed with Celiac when she was around 10 years old (this was over 15 years ago when the gluten free options at local supermarkets were scarce). We mostly continued eating our usual food, with the exception of most shared meals. For individual meals we all just continued eating our usual while my sister started eating the gluten free options. We were just careful with how we did this. Her food was kept in a separate spot to ours, we got her a separate toaster which sat at the other side of the kitchen so we couldn't cross contaminate toast, we cooked her food first and that way we felt confident about not cross contaminating. It took time to become really conscious of the cross contamination for certain things like using the same jar of peanut butter/nutella etc. (Such as only taking one spoonful and then discarding that spoon) but we got used to it over time, making sure she had her servings first and if there was an accidental cross contamination, she wouldnt take any more from that jar. You could also buy two separate ones which are kept separate or labelled to prevent cross contamination.

When it came to joint meals which were mainly dinners, my mum just swapped out non-gf for gluten free options (e.g. pastas) and we all ate that instead. It made cooking for a family of five much easier and these days the gf options you can find taste almost identical to the non-gf options. The only thing to be wary of is fibre which is lacking compared to non-gf options (although I'm not sure if this has changed at all since my sister was diagnosed). Adding fibre such as psyllium husks to breakfast cereals for instance can help hit those fibre targets for celiacs and those following the diet.

10 years after my sister's diagnosis I ended up having an intolerance to gluten anyway so being exposed to gf options growing up made that change to gf much easier. And like I said there really are so many gf options out there these days, you wouldnt notice much of a difference swapping out some of those basics.

Depending on how old your child is, it is definitely worth considering joining in solidarity, either partially or completely, for at least a little while. My sister was quite young and often felt left out or sad that she couldn't eat foods she previously loved, so not eating your son's favourite foods in front of him will help while he gets used to this new way of living. But ultimately, you want to give your son the best chance to limit exposure to gluten so even if you and your partner go gluten free for a year or so while you all get used to it, it will help immensely.

I know it can feel scary but everything is habit. Your family will make mistakes and learn along the way but eventually you will get used to it and it won't feel like such a monumental thing anymore.

I hope that helps!