What you’re experiencing is very common, and I hope you can take comfort in knowing that most people hide things from their therapist at one point or another. To get past this, though, you’ll want to understand more about why sharing your marital challenges with your therapist is so hard for you.
People have many reasons for hiding the things they most need to talk about. Sometimes they worry that the information will make the therapist view them in a negative light (say, admitting that they’re having an affair or that they scream at their kids). Or they might find the issue embarrassing (say, anything to do with sex). Other times they’re in denial (Yeah, I drink more than I should, but it’s not affecting my life in a significant way). Sometimes people hide things because they worry that they won’t be believed (they may not have been in the past). And sometimes people hide things to avoid not just the therapist, but themselves—to avoid confronting their shame or pain, or the truth they know they need to tell.
Therapists are also familiar with something called a “doorknob disclosure,” in which a patient says something she should have said during the session on the way to—or while standing at—the door. “By the way,” a patient might begin casually, although whatever comes next will be anything but an offhand aside. It’s not uncommon for patients to go through an entire session talking about this or that, only to spill something important in the last 10 seconds (“Oh, and just for what it’s worth, my biological mother found me on Facebook”). In these cases, people don’t want you to have a chance to comment, or they want to leave you feeling as unsettled as they do. (Special delivery! Here’s all my turmoil; sit with it all week, will you?)
But perhaps the most common reason for hiding information is this: Once you bring something up, you might have to deal with it—not just the situation itself, but the uncomfortable feelings that accompany it. In your case, if you start crying whenever you consider talking about your marital strife, you probably have some deep feelings about it. There may be sadness, or anxiety, or shame, but I imagine there’s also fear: fear that your marriage will end as your parents’ marriage ended, fear of the changes that you and/or your spouse might need to make to improve the relationship, fear of the unknown. How much easier it sometimes feels to cling to the familiar, to let sleeping dogs lie.
But while sharing difficult truths might come with a cost—the need to face them—it also comes with a reward: freedom. The truth releases us from our internal prisons and gives us the possibility of moving forward. The longer you wait, however, the more entrenched the problem becomes. Which is why instead of worrying about whether you’re wasting your therapist’s time, you’d be better off focusing on how you’d be wasting more of your own time if you were to leave and wait for something to shift—time you could be using right now to improve your marriage.