Getting family on board with eating changes

In the long term you really are going to learn to live among people who are not the same as you.  In the short term, you might consider finding recipes that you can both eat, with an added carb for your partner.

In the very early stages, you'll be on your own with liquids and purees etc.  

This is an opportunity for your family to adopt healthy habits, but if they're not interested, you will have to be strong enough to do this by yourselfd

This may sound mean. But worry about your eating. People usually follow by example. 

My partners both eat stuff that I don't touch but they're kind enough to a) stick to things that aren't my favorites and b) keep those foods in their offices instead of out on the kitchen counter or some place that I'm frequently around.  I don't buy snacks for people, though, so they have to get it themselves and are more likely, now, to just eat that stuff at work or when they're out or order it in restaurants.