Have a white candle (since it sounds like he didn't do anything bad to you, luckily, otherwise I'd advise black, to expel the negativity), a sieve, and some paper and a pen.
Write down anything about the relationship that you can remember and think is important; good memories, places, objects, the things he did, things that make you happy, plus all the things that made you unhappy, like long term problems, his flaws, your flaws, things that irritated you, etc.. You might figure out what's going on and what you want to do before you even get a chance to cast this spell. But just in case, I'll finish it anyway..
Light the candle and grab the sieve.
Put that paper into the sieve and hold it over the candle flame to let it burn into ashes, thinking of moving on with your life and where you want to be.
Now you can take the ashes (perhaps in a bag) either to a running stream of water, or to the beach where there is plenty of purifying salt and water (In general, anywhere you feel uplifted). Let the ashes scatter over the water. Go home. Do something to relax, perhaps take a shower to wash away your old feelings, tell yourself you're done with it, and then move on.
To see the world in a grain of sand, and heaven in a wild flower. To hold infinity in the palm of your hand, An eternity in an hour.