A potential ‘anti-spice’ that could dial down the heat of fiery food

I like spicy food and use so much pepper and chili that also my girlfriend got used to it. But when I cook for other folks I don't know yet it's sometimes hard to correctly estimate the appropriate amount to add. And if it tends to be too hot for someone, it'd be great to have an anti-spice to offer. Of course you can also add something creamy but that also changes the look, texture and taste.