Faithful:

It is commanded by Allah that we be faithful to our spouses. Adultery is a capital crime in Islam that is punishable by death. However there are various forms of unfaithful behavior prevalent among some Muslims. The most common form is maintaining friendships with the opposite sex over the boundaries set by Islam, and the misgivings of the spouse.

Fun:

Couples that do not laugh together have to work on sharing some fun times. The Prophet (SAW) was known to play with his wives. A simple walk in the park can add much spark to the relationship. Taking up a sport together or watching clean funny movies is another way of sharing a laugh.

Friends

It is okay to have individual friends of the same gender but couples must also make effort to have family friends so that they can socialize together.

If there is friction being caused by a certain friendship it must not be pursued at the expense of the marriage.

Prophet Muhammad (SAW) advised us to choose God fearing people as friends since we tend to follow their way. Friends should be a source of joy and not mischief.