Here is how I have approached this topic through the years:
1. Dont teach or preach: The more preachy you are the more it turns them off, it doesn't matter what things you find or authors have found...etc. You also can't teach people that aren't receptive to hearing your message. You can control yourself, so let them see what you are doing. I've found that for myself things like not eating the bun when we do go out to eat have influenced my youngest son, who at times only wants to eat the meat, and the apples.
2. 2 week trial: Ask your wife to do it with you for 2 weeks, to help support you in trying to stick to it, explain how much harder it makes it for you. If she agrees that is over 1/2 your battle right there. So for a family dinner that is paleo you now have the option of feeding your child entirely paleo or he can have the main meal plus some grains. For example, my wife and I eat paleo and sometimes for the kids they will have what my wife and I are eating but instead of having sweet potatos they will have mac and cheese that night. For the most part though they don't notice if we don't make them a "starch" typically their meal will be a veggie a fruit and a protein, while my wife and I will have 2 veggies, and a protein.
The drawback here is that if she does agree you now have to be open to try whatever she might want to at a later date. Through the years I have done gallbladder cleanses, smoothie diets, the Velocity diet...etc with my wife, not for her but for us as a couple. It's one of those things that ow we are like, "do you remember that velocity diet, man we got skinny but ugh it was awful!"
3. Kids: Well you saw what I said about dinner, so what about breakfast, lunch and snacks? Buy less crap, but not completely, let your kid pick a crappy snack or 2 for the week. As for lunch that I know some families that pack their kids a paleo lunch...etc but that is just not a battle I have chosen to fight.
"And for crying out loud. Don't go into the pain cave. I can't stress this enough. Your Totem Animal won't be in there to help you. You'll be on your own. The Pain Cave is for cowards.
Pain is your companion, don't go hide from it."