It's easier to write about heartbreak after you've had your heart broken. You have more material to draw from, you can extrapolate from your own experiences and make reasonable assumptions about how your characters would feel and act.
Patrick RothfussโI will admit, I've never had a student offer himself up for a vicious beating in order to prove he's worth my time.โ โThis was nothing... Once I jumped off a roof.โ
Patrick Rothfuss