I would describe "one heck of a ride" similar to the feeling of being on a roller coaster. Roller Coasters are really fun, but the best parts are the drop, turns, loops, etc. Anything that can get your blood pumping. I think that is what "one heck of a ride" being used to describe love means.

Heck is a way to smooth out the word "hell"...

Heck = hell "One hell of a ride" = One very exciting or unnerving experience, a very emotional situation.

In this context "a ride" is a journey. Not a physical journey, like from your house to your job, but more of a life journey. The phrase "one heck of a ride" is usual meant to look back with nostalgia and fond memory. It also implies a bit of excitement and adventure. For example, "I went to university in another country far from home, I made lots of friends and saw many wonderful things. It was one heck of a ride". Another example, "I met this crazy girl on my holiday in Australia, we danced all night, we surfed, we shared many secrets. It was one heck of a ride." Just like a ride in a car has a definite beginning and end, "one heck of a ride" implies a definite phase during a person's life. When you use it you are usually looking back in time on something which was exciting and good, but which is now over.