The mental effect you two have on each other is strong, but not necessarily pleasant. There is an air of intensity when you're together, and your partner pushes you to confront the deepest, most complex and potentially frightening issues in your life -- your past, for example, or your attitudes about death, sex and spirituality. The way that they try to force you to face these issues down and ferret out your deepest, most buried emotions is probably pretty uncomfortable for both of you.
You likely have arguments over your differing viewpoints -- or you fight when you don't feel like obsessing about such issues all the time. But you feel compelled to do it, as if your time together would be wasted on mere small talk or superficial communication. This aspect could have a positive effect, as well; it encourages transformation to a higher mental plane, or a higher level of self-awareness. But the likelihood is more that you'll mentally torture yourself due to your partner's effect on you. You argue and obsess about things that never bothered you before you two met, and you probably experience bad dreams or a suppressed mood when you're awake. They might try hard to have control over your emotions and thoughts, which would really push this influence to its limits. Try to give each other, and yourselves, a break from time to time, because this kind of influence will wear you both out if you're not careful.