Friendship

what do you call two best friends guy and girl who live apart but some how manage to do everything together and read each other's minds. when we talk we end up talking about something the other was talking to someone else earlier that day or end up getting hair cuts the same time and find out after or just finishing each other's sentences. I know it's silly but I'm not even this close to my fiance he and I never talk and my fiance only jokes with me when I'm the joke to laugh at. it's just amazing my best friend and have a better connection. why do relationships have to be so hard?