I don't think that scar tissues make relationships wear out, I think values misalignment does.
Sometimes it can also be a character flaw.
While I believe our values were aligned, my partner was very critical about almost everything I did. She was not supportive of my goals. She dismissed my interests, and she often criticized how I did things. We were from two different cultures, but we strongly agreed on many important points (including how to raise children). It was the little things that bothered her. This was bad enough that even friends who visited us noticed and admonished her for treating me like that. A therapist friend also noticed and tried to help her. Probably due to how I was raised, it took me years to realize myself that there was a problem, and it took a few more years for her to acknowledge the problem herself. It was when she realized that her mother treated her the same way. Unfortunately she felt that she was unable to change. I credit it to our shared values that I stayed with her as long as I did. This issue would have almost destroyed our relationship if it hadn't been ended by cancer instead.
Sometimes it can also be a character flaw.
While I believe our values were aligned, my partner was very critical about almost everything I did. She was not supportive of my goals. She dismissed my interests, and she often criticized how I did things. We were from two different cultures, but we strongly agreed on many important points (including how to raise children). It was the little things that bothered her. This was bad enough that even friends who visited us noticed and admonished her for treating me like that. A therapist friend also noticed and tried to help her. Probably due to how I was raised, it took me years to realize myself that there was a problem, and it took a few more years for her to acknowledge the problem herself. It was when she realized that her mother treated her the same way. Unfortunately she felt that she was unable to change. I credit it to our shared values that I stayed with her as long as I did. This issue would have almost destroyed our relationship if it hadn't been ended by cancer instead.