Imagine a strong friendship between a man and a woman who are not married to each other and are not planning to marry each other. They are just friends, but very close friends. They can share so many things between them. The relationship would be very complimentary in nature. They can support, encourage and motivate each other to achieve better things in life. They both can be inspirational to each other.
There would be no binding or expectations in such relationship. If they are together, it is only because they like to be together. There is nothing sexual about such relationship. Both would not be averse to a touch or hug for offering comfort, support and a feeling of togetherness.
You can call such relationships impractical today but a day will come when such relationships would become more common. It is a very healthy and happy relationship and it would be wonderful if the society does not impose the usual restrictions on this.