I wished you had posted this under the Estrangement heading. I hope those posting there get to read this.
I'm glad for you.
It seems to me that you both showed some maturity and a willingness to move into a better place with your relationship, which is commendable.
How touching that she gave you the release and comfort of telling you how important you were to her, and how she loved and trusted you.
No doubt this is a reflection of how much work you invested in the relationship.
Some people cant get that far, and hand on the bitterness and anger to the next generation.
They never come to some type of understanding or acceptance.
What you have described is something we can all hope for, and work towards with some of our more 'difficult' relationships.
Your family will benefit for generations to come I'm sure, from the healthy path you and your MIL have set them on.
Best of luck