The significance of space in a relationship is a very important idea to understand. No matter the relationship, no matter who is involved, everyone needs time together and everyone needs time apart. It's easily understood that people need to be together in relationships, how else could the relationship ever come to fruition, grow and survive? What's harder for some people to understand is the significance behind the need for personal space. Many insecure people constantly ask the other, "Why do you need to go out and do [such and such] without me when you've got me? Am I not enough?" Well quite honestly, their need for personal space is not about you, it's about them; don't take it so personally and don't hold them back.
Everyone is an individual first and foremost and entering into any kind of relationship, be it with friends/lovers/or a parent and child sort of combination, does not erase that simple fact. You are already a significant someone before you ever become closely involved with anyone else and you will continue to be that person long after the relationship is tested, tried and true or doused out and simply a part of your history. Because of this, it is imperative that you remember your own personal goals and dreams and continue to be your best self for yourself as well as for the other person. You need to remember to continue to be you. To accomplish this it takes time and it takes space.
If one is constantly forced to focus solely on the dynamics of the relationship and on who they must be in order for that relationship to continue, they will in time loose their own identity; this cannot be helped. When a person has to give up all off him/herself in order to make a relationship survive, that person will become angry when the honeymoon phase is over and they finally figure out what has happened. In turn, they will blame their loss on the other person involved in the relationship; the very one they chose to give it all up to in the first place. A fun conundrum don't you think?
The easy answer to this is to be yourself first and to enjoy a happy and fulfilling life which you can share with someone else. Create the space and time you need to follow your own ambitions and purpose. It is unreasonable to go into any relationship expecting it to fulfill all of your wants and needs; it is unfair to expect someone else to supply the perfect life for you; that's actually your job.
As far as it being easier to take more space than to give in relationships - I think this really depends on the individual person/people involved. For myself, I don't believe this statement to be true. For some, I'm sure that it is.
Relationships are formed for various reasons. Some reasons are good and some aren't so much.
Many miserable relationships are based on the "what's in it for me" factor. This is the dysfunctional relationship between two people that can't fulfill their own needs so they look to another to do it all for them. When the other person falls short of their unrealistically great expectations, they show their disapproval under no uncertain terms and out come the fisticuffs once again.
In these challenging relationships, each person wants to govern over the time and space of the other person. Sometimes they want to do this to simply be in charge to wear the pants in the relationship and sometimes they want to control the other person's space simply because they don't care to be alone or don't want the other person to have a life outside of the so called life they have together. They feel that if the other person is out there having an enjoyable time away/apart from them then the other person really doesn't love them as much anymore that they are in fact loosing them. What people in these relationships don't understand is that if you hold a person down or back long enough, you are actually more likely to loose them.
In healthier relationships based on true admiration, respect and love the scenarios are oftentimes quite different. People enter into these relationships because they truly enjoy the other person and want to bring them happiness and love; they enter into these relationships to give to that person. They don't enter into these relationships because they feel empty or have a personal hole that they need to fill up fast. These folks are already fulfilled and happy and want someone to share all their blessings with.
Because of this, these people find it easier to let the other person continue to be, learn and enjoy life outside of their intimate circle. They understand that in order to have a wonderful relationship together, each person needs to have some time and space apart to be able to continue to grow and be their own special self. These people feel much more secure in their relationship and the difference here is that they are not expected or forced to give time and space, they simply give it out of their own thoughtfulness and love for that other person. The caring feelings and actions associated with these feelings are mutual, corresponding and are grounded in the sincere appreciation for the other person. This alone is the big difference.