You might think everything's fine and dandy between you, when really, you're not connecting at all -- and neither one of you realizes it until it's too late. Remind yourselves repeatedly to be completely open about your feelings, because otherwise, you run the risk of being misunderstood or misinterpreted by your partner. You're rather sensitive to each other anyway; they're capable of pushing your buttons without even realizing they're doing so, and vice versa.
If you misunderstand where they're coming from, or if you feel misunderstood yourself, then that only creates more opportunities for oversensitivity or hurt feelings. It's hard to trust each other when you don't even feel as if you're being seen for the person that you truly are, but you can take the responsibility for that into your own hands, at least to a certain extent. If you allow yourselves to dissolve into tears or tantrums in an attempt to get your point across, you can be relatively assured that that only leads to further confusion. Gentle, open and honest communication, on the other hand, helps clarify any issues that arise between you.