I think this neatly sums up part of the problem:

Well, as usual, there are some excellent comments here on this subject. I would only ad that in today's society, which is highly commercialized, people feel obligated to be part of a couple. Movies, books and ads romanticize couples and people feel ostracized if they
are not involved with someone.

Simple Suggestions: 1: Turn off the TV and the computer. 2: Invite some friends over for boardgames/storytelling/joke sharing. 3: Learn to sing/play and instrument & join a group for practice. 4: Learn to dance and throw a dance party. 5: Join a group that seeks to improve a situation you are concerned about. Basically entertain yourselves and act the way our great-grandparents did - with each other rather than with expensive technology. Meetup.com is a good tool for meeting real people with similar interests.

To your first two questions: fear and improper communication.

Fear is a powerful drive. Fear of judgment, of ridicule and rejection. Or sometimes it's fear of being hurt, especially if you've been hurt before. All the can cloud our judgement and rein us in from going after what we want.

Improper communication is when something seems
to be obvious or clear to one person, when it's anything but to their partner. When we say "It's fine.", when it isn't and refuse to talk about. When we want or need something but don't say it and get frustrated that they don't give us what we're looking for. All of this serves to drive people appart.

For your last question: trust, proper communication and faith.

Trust is so fundamental that without it you don't have a relationship at all. You just have a series if interactions that will most likely be bad and harmful. You can trust them not judge or hurt you. Without trust you have no real basis by which to communicate.

Proper communication is what is born of trust. Judgement free exchange of ideas, hopes and fears. The ability to say what you want in a way your partner can clearly understand and they do the same with you.

Faith is one I imagine most people here will bristle at, but hear me out. I'm not talking a higher power. I'm talking faith in yourself and your partner. You can never truly know another person. There will always be some part of them that is theirs alone. Which means at a certain point you have to have faith that your judgement was sound, that your trust wasn't misplaced, and that you expressed yourself clearly. You have to surrender some modicum of control, pass the ball to them and see what happens.

Everone is holding out for a 10...