What Is This...

I've lived in a sexless, cold relationship for many years.  What's up with this? I seriously can't wrap my brain around this concept.  Are there people who, as they age, just don't like physical or emotional intimacy anymore.  Is the initial intimacy for the sake of snagging a mate of some sort... and then you try to hold on to that mate for a while... and then... what... you just don't care after a while... and then... there you are... no intimacy.  Anyone with insights???  I miss the touch of someone who loves me!