The communication between you will be fraught with a deep, dark energy that you'll both find simultaneously frustrating but compelling. Your lover may find you secretive, and you may be secretive with them, at least when it comes to your very deepest emotions; after all, part of what has brought you together in this life is a past-life connection in which expressing yourself in an honest way was not allowed -- perhaps it was even criminalized. But though those old feelings are still lurking in your subconscious mind, making it difficult for you to trust your partner and open up to them, they really don't have much to do with how you'll interact today.
That's the first thing for you to realize as you work to overcome this communication problem, and you should work to overcome it; otherwise, you won't be able to develop a lasting sense of trust and honesty with this person. And the truth is, they can help you. They can teach you how not only to access those deep, dark, scary feelings, but how to bring them to light and talk about them openly. Don't misuse this gift, however. Your tendency may be to use this person as a sort of sounding board for all those heavy feelings, because they'll be quite good at processing them for you; but the real work of processing through them should be on your own shoulders. That's the only way you'll rid yourself of this heavy karma and move on to the next life with a lighter load.