At least one of you will have a way of using versions of the truth against your partner, in a bid to control them. During arguments, one of you will use subtle psychological tactics against the other as a way of trying to gain the upper hand. When your partner gets angry, for example, instead of talking things out and dealing with their feelings at face value, you might dig deep and develop a psychological explanation for the origins of their anger.
In short, you'll play armchair psychologist together, but in a way that's more hurtful than helpful. Part of the potential for damage here is that you really will have a high level of sensitivity to each other's inner thoughts, feelings, fears and desires, and it won't be difficult to analyze each other. But rather than offering your analyses in a genuinely helpful spirit, you'll present them in an effort to make your partner feel vulnerable and flawed, helping you gain power. You may even convince each other of the truth of your psychological portraits, even if they're at best a distorted version of the truth. You can turn this influence around, though, if you capitalize on your deep, sensitive understanding of one another's psychology but don't use this perceptiveness as a method of domination. Instead, use it as a tool in becoming closer and more intimate with each other, and in building a foundation of trust.