The answer to that question is dependent on individual sex drive and the physical attraction between couples.
I was previously in a relationship for many years and sex was never high on the agenda. I was never really physically attracted to my partner, but we had a very comfortable amicable relationship.
However, I’ve discovered sex with my SO and it is fantastic. I’m very much physically attracted to him, and I have ‘feelings’ whilst having sex that I haven’t experienced before.
Although I now think that sex is an important factor in a relationship…I think you also
need to have other ingredients like total communication, comfortableness, have fun and keep the relationship alive…free from complacency.