You can do certain things when you're just dating someone that you can't do when you're married to them. For instance, when you haven't put a ring on it, you can take a girls' trip to Costa Rica over Christmas, and though your significant other might be irked, oh well — it's not like you're married.
When you're married? Yup, enjoy watching your friends' Instagram feeds flood with photos of tropical paradise while you hang out at your in-laws' house.