Though you might get along really well for a time, you realize after a while that there's some sort of disconnect in your communication. At some level, you aren't entirely honest with this person. This could be a major pattern of willful dishonesty, but it's more likely to be as minor and intangible as you holding a part of yourself back due to insecurity or past experiences -- and then your lover follows suit, because they feel vulnerable and self-protective when they pick up on this strange vibe.
Of course, when we're courting a new lover and falling in love, it's perfectly natural to put our best face forward -- but doing so hides that whole other side of ourselves that comes out later, the side that isn't so kind and smart and well-thought-out. If we've been in troubled relationships in the past, in which we learned to keep parts of ourselves secret as a method of self-protection, it's hard to relearn to live and love openly. But the point of a good relationship is to be ourselves, warts and all. You two might have gotten involved with each other before you really knew each other, so your expressions of affection might be less than sincere -- you might not even be certain of your own heart! It's very possible that you have a confusing effect on your partner, making it hard for them to think clearly when you're together. The lesson of this aspect is for both of you to take it slowly, be yourself and communicate as honestly as you can -- even when it's uncomfortable to do so.