"The strength of a relationship is in the repair." – Terry Real

All relationships will have "ruptures". That's just the nature of this life, we are limited creatures with imperfect data, we will step on each others toes. And so all relationships of any variety require repair. 

If a difficult conversation about "hey you stepped on my toe" can not be had, then that is a very weak relationship. And really strong relationships are not ones where no ones toes are stepped on, but one's where toe stepping can be discussed and resolved.