Most of us have a quite good working conscience and know too well when we didn't behave the way we should have, our weren't able to live up to our own standards. Some of us try to ignore the nerve-wracking knocking of our conscience on the doors of our mind, but there aren't many who are successful in doing so. So noone really should be in need to tell you whether you're right or wrong. You should be able to see it yourself in a quite moment of leaning back and pondering. If there is something bothering you - its time to rethink our actions.
But many times after sinning, being mean or simply not doing good enough we don't have the courage to stand up and fix what we have broken.
What you don't repair will remain broken. If you have an honest interest in a relationship , and that should be the case if you befriended/married the right people, you might also have an honest interest in fixing the cracks.
So go ahead and fix it. If you can't fix it : make it less hurting. Clean your conscience, make a move and step out of you're comfort zone. Forget the ego.
The other side might be waiting for your move, struggling the same way
The rarest separations are pleasurable.
1) Rethink the situation :What have you done wrong ? What could have you done better ? What do you still stand behind ? Why are you upset ? Why is the other side upset ? How can you change it ?
2) Rethink your relationship :What does the other mean to you ? Why do you like them ? Why could they be liking you ? Is the issue worth risking the relationship ?
3) Rethink your character :Do you often react in a way in which you wish you shouldn't ? How are you planning to change it ?
Once you apologize for something you will be a lot less likely to repeat the same behaviour. Apologizing is never easy in the first moment. Admitting ones own faults to someone we have wronged without trying to justify is never a pleasurable experience for the first seconds. It might take some mental preparation time. But its worth it.