The End Of A Relationship

My husband and I have chosen to end our relationship with my brother and his wife. It has been a roller coaster of emotions for the last four years. Both sides are at fault for where the relationship has ended up. I have been doing a lot of thought work on the topic and have discovered good things and bad things about myself. My question is where is the line of trying to endure their hatred towards us and deciding things are over for good? Even though at the time I felt confident about the decision to end the relationship, I sometimes feel guilty or think I should have been stronger. Also, they believe pretty strongly that we acted spitefully and never took them into consideration, no matter how many times I told them that was never the case and we wanted only what was best for them. How do I accept them believing what they believe even though I know I’m a good person and acted from a space of love?