Decision: Get back together or break up forever?
Take the pressure off of yourself with the following thought: There is no "wrong" action, just choices and consequences.
If you go back and it turns out to be the wrong thing, you'll know for sure. If you do not go back, you may always wonder if you should have given it one more go, or you may feel peace and relief of not having the anxiety for the same thing to happen again that had happened so many times.
There's a part in each that will be resolved in the outside world, and a part in each that needs to be and can only be resolved within you. If you feel hesitant, it could be intuition or at this point it could be self-protection/fear of not wanting to return to that which you know has the ability to cause you great pain.
Wherever you go, go fully. If you decide to go back, do so with optimism and not with anxiety. If you do not go back, move forward in life with curiosity to the new and not with regrets over the past. There is no wasted time and no wrong choices. Life is just a mix of loving and learning and in either choice,
you will do both.