A lack of this weakens a relationship immensely

Many people don't realize just how detrimental a lack of self-disclosure can be to a relationship.

How frequently do you share your feelings with your partner? Do they share their feelings with you? 

Emotional self-disclosure, the exchange of intimate feelings, is instrumental to a relationship's health. One person speaks, and the other listens intently, provides validation, and demonstrates they care. And vice-versa. 

The responsiveness of the listener is integral to self-disclosure, building trust and intimacy. 

When people no longer share their feelings with a partner -- or share them with someone else instead -- the partner loses an opportunity to build their relationship and the relationship in turn suffers. When this becomes a habit, it may very well indicate that someone is oriented away from a relationship rather than toward it. 

A lack emotional intimacy and transparency tends to characterize relationships between casual lovers or acquaintances. That isn't to say the people in such relationships can't develop a deeper bond over time, but usually both parties know what they're getting out of it -- whether it's no-strings-attached fun under the sheets or networking/career-enhancing opportunities at work.

But a romantic relationship (or even one between close friends) should never be this impersonal. When it is, a breakdown in communication is often at fault. One partner has ceased opening up to the other. The latter feels neglected and in turn closes himself up emotionally. It's a vicious cycle that erodes the warmth, trust, and security people ought to share. 

To salvage the relationship, one person is going to have to break the stalemate -- but it shouldn't be the same individual each time (assuming the pair hits this snag more than once).

Air your frustrations without being rude or confrontational. Strive to be understanding, not judgmental. Aim for compromise, not conflict.

This is the stuff solid relationships -- those poised to last -- are made of. Anyone who thinks their relationship is immune to the perils of a lack of self-disclosure is kidding themselves.