Your comment about your MIL never letting go of her h's A, reminded me of a man I knew growing up. See if any of this resonates with you.
I grew up with a neighbor who was a retired Army Colonel. He had been a POW for several years, in Vietnam.
He and his wife had 5 kids. Years before they moved into our neighborhood, the Colonel had had an affair with some OW, brought her to work functions and evidently really cared for her.
So, how did I, a young 17 y/o neighbor girl, know that the Colonel had had an A?
Oh, I knew b/c everyone knew that, b/c "Mrs Colonel" made sure we all knew, so we would not think he was such a great guy.
There were times I wanted to ask the Colonel about his POW experiences. Mrs. C- would steer the topic away. I truly believed for years, that she was protecting him from a bad memory.
Then l learned that she simply didn't like him getting that type of attention. At the time we knew the family, (Post Affair) the Colonel was kind, funny, handsome, strong, and really just a great guy. Yes, we all did like & admire HIM.
In contrast, She was a bitter woman, who made a snide remark about her h at every turn. From how he over cooked the grilled meat, to undermining the value of a reference letter he wrote for my h to how poorly he mowed the lawn and "ruined her flowers AGAIN". She could NOT give that man a kind word to save her soul.
She never praised him in front of her kids, or us, and she would undermine any compliment others would give him. She seemed to live to make him pay. I'm not exaggerating.
She was NOT kind to him at all. Seemed like she never let him forget what SHE had endured & what HE had done TO her AND their family.
Today, over 3 decades later, only 1 of their 5 kids is married, (their only son). It's his 2nd or 3rd marriage. The others (all girls obviously) are all single. 2 never married, the other 2 keep on getting married repeatedly. So none of their d's had their first m's work out OR even tried marriage...
The choice that Mrs C- made was the worst of all choices.
She could have divorced him. She could have gone to counseling and therapy, to learn how to forgive him.
But instead, she made the worst AND most tempting choice; she stayed married AND she stayed miserable. And made it lousy for HIM too. She never let Colonel forget his sins.
She held it over his head like the Sword of Damacles. She threw it in his face (or threatened to) every time they fought or disagreed.
She did NOT Forgive him and she did not even try to. Not in a serious humbling way. Ironically, from where we sat & from what WE saw, HE was the victim and she was the wrongdoer....she was not a woman we sympathized with.
She should have let him go when she found out about the A; OR as soon as she realized she could not forgive him; OR she should have learned how to forgive.
She could have bequeathed her children a beautiful legacy. She COULD have taught and passed on to them, the concepts and practices of true forgiveness, real redemption, deep love and full commitment.
Instead, she passed onto them suspicions, distrust, cynicism, bitterness and big time grudge holding. She did not think he "deserved" forgiveness -- AND she overlooked how many others were affected by her choice not to forgive.
I wish she had heard what I heard awhile back, which was
"Holding onto anger, to punish someone else, is like lighting yourself on fire,--- to get smoke in their eyes."
You won't be repeating that^^ for your kids, thank God.
M: 57 H: 60 M: 35 yrs S30,D28,D19 H off to Alaska 2006 Recon 7/07- 8/08 *2016* X = "ALASKA 2.0" GROUND HOG DAY I File D 10/16 OW DIV 2/26/2018 X marries OW 5/2016