Despite how the old "sticks and stones" saying goes, words can often cut deep. And when something hurtful is said, it's not easily forgotten. There are certain phrases that should be forbidden in a relationship, and knowing them now might help prevent them from spilling out later. Regardless of whether you're in the heat of the moment or simply not aware of the impact of your words, you should always be careful and cognizant about what you say. See 10 things your partner should never say to you.