Go through this article for sure...
Fighting For Space

Points to ponder :
1. No possessiveness/domination.
2. Enjoy and do what you love or atleast indulge yourself in hobbies...
3. Make the partner feel comfortable.
4. Give enough independence.
5. Spend some time away from each other[if required] which inturn helps to lessen the space between the two.

I just loved this sentence from the above article.
"Space is all about how you adjust yourself without losing the 'You' in the 'us'".

It is a magical bond between two different personalities which includes understanding, belief, respect, handling conflicts, compromising when required, luck and giving each other enough space. This might result in a successful marriage. But still, there is one most important aspect in marriage. It is being friendly with each other. This is where any person can have a long lasting and a wonderful relationship.

I just got some links regarding the same.
How can we step into our spouse's world
Different views of marriage by different people
Nurturing friendship in Marriage
Learning friendship in Marriage

Now just let me know your views regarding a successful marriage.