Great responses so far.

Thank You.

There's really no one-size-fits-all answer to this.

We're all different and what's important for some may not
be important for others. It ultimately depends on your
personal beliefs, physical desires and the nature of your
relationship.

Some people may have a low sex drive, others a high sex drive.
The sex drive may change as we age. Some people may have an'
underlying medical condition - and be in chronic pain.

Others may have a set of religious beliefs - (sex goes with marriage
only). Still other may want to date for a longer period of time
before having sex, and the list goes on.

For some intimacy doesn't necessarily have to include sex.
It can involve things like cuddling, kissing, holding
hands, massages, and many other things.

Relationships have their ups and downs. To me, communication is
important - plus having the time to get to know each other.
I also like tenderness. But it is the rarest emotion one
encounters.

In personal intimate relationships - you need time. Active time.
Whether it leads to communication, as it frequently does, or
to a romantic situation, or both. Too often when people
are dating, they're rushed into being sexual - a question of
time again. I feel that it's wise to have taken the time
to discover each other - if both like what they've found -
it can be exhilarating - and sheer magic.

All in all I feel that sexual activity is not necessary for a
healthy personal, intimate relationship. It's a bonus. But
many people do live happily without it.

There's much more at the following link:

http://healthline.com/health/healthy-sex/is-sex-important-in-a-relationship#

Every relationship is different. Every single one.

Sex will be important in some, less so in others, not at all in still others.

No one knows what goes on behind closed doors. No one should. The question will remain unanswerable and rightly so.

Psychologists advise that it's better to know the pros
and cons of whether to have sex before marriage or not,
weigh them up, and then make an informed decision.

The following link explains further:

http://marriage.com/advice/physical-intimacy/physical-intimacy-before-marriage/

Some of the pros listed are - 1) Assessing sexual compatibility.
2) Identifying sexual problems. 3) Better understanding of
partner. 4) Better intimacy with partner. And so on.

Some of the cons listed are - Fear of pregnancy. 2) Fear of STDs.
3) Fear of break-up. 4) Single-parent situation. 5) Lack of maturity.
6) Moments of guilt. 7) Less understanding partner. 8) Hurting
religious sentiments.

Here's another interesting link:

http://thehealthy.com/family/relationships/is-sex-important-in-a-relatiosnhip/

Sorry for the typo.

Here's the link again:

http://thehealthy.com/family/relationships/is-sex-important-in-a-relationship/