Relationship is not all about sex but it is about love, loves comes with a lot of other elements, it comes with understanding, trust, patience, romance, care, helping one another to become best version of himself or herself, all these are needed for the relationship to grow.
Sex is a very important part of a relationship but it is not all that us needed to make a relationship to work. To keep a relationship, other elements of love as stated above are needed to keep the relationship stronger and exciting.
Great question, Love and Sex both are very different things but when you are expressing the love then automatically love turns to sex (If you are couple) but if you are not couple then love is care and sex is romance and both are running simultaneously...
Relationship is about love, but it does not have to be about sex. More than this, a relation is about understanding. It is about knowing the other person and helping him or her through different aspects of life. Yes, intimacy and sex is a vital part of any relation, but it is not the only thing to consider. You need to have the other components of a relation for it to work.
Having deep understanding of the person, a good sense of humor and the ability to take care of certain needs of your partner, helps you build your relation. These things make it stronger. You can then add the flame of romance and sex to fortify your bond and make things interesting.