Once if a relationship is broken then it's hard to mend it. They are so delicate that even a small issue or simple misunderstanding can lead to quarrels. To get back the same intensity of affection in the relationship is a big task. The cause for the easy breaks in relationships are mind products, subjective to each person etc.
Relationships start blindly by peripheral understandings and attraction. It proceeds through adjustments, forgiveness, and understanding. Getting back into the relationship, though difficult, is possible if approached the issues with the right understanding and mind to change and mend.

Understand the Reasons Behind Breakup
To resolve any problem, recognition of the reasons is crucial. Without knowing the root cause, relationship issues cannot be repaired. It can be a past reason which is now absent or a still enduring reason.

Forgiving is Magical
Once the issues are dug out, the next step is to forgive the mistakes of both the partners. If you still hold on to the mistake committed by the partner, then it may cause another breakup in the future.

Renew the Commitment
Once you are back on track, renew the commitment and let your partner know the new resolutions and decisions.

Change Yourself
You may not be able to replace the partner as you want, but you can very well change yourself. Changing yourself is the better way of resolving the issues and renewing the problems.

Communication is the Keystone
Most of the issues in relationships can be resolved with right communication with the partner. Let the communication be creative, rather critical.