I had it explained to me in a very simple terms from a good friend. He never understood his last divorce until he was at the ranch on his four wheeler and going through his normal routine. He was on his trail, when all of a sudden for no reason he just takes a left and leaves the paved trail. He felt alive and for the first time excited because he didnt know what was going to come next. He just needed to leave the rut of his normal routine. This may or may not be happening to you, but I believe if people were told the truth about marriage from an early age instead of being sold a fairy tale prince charming on white horse, people would be better prepared for the waves marriages go through.
I like the video of "it's always sunny in philadelphia charlie wildcard" scene. If you havent seen it youtube it.
My marriage was like yours in the case that i never abused her, and was a good husband and father, just didnt take the nagging seriously enough, because there wasnt enough in my eyes to see concern. I have learned now that any nagging is serious and shouldnt be taken for granted.
Best thing we can do is learn from our mistakes, and become a better person.
M:43 W:33 M:10 T:11 D:6 BD 8/12/17 Divorce Final 1/23/2019