If the pre nup is like the one Grace was made to sign, she loses the kids no matter what. Since it is said they don't live together, I assume they've already go to separate lives, but geez she needs to put on a happy face for all their sakes. She's a total failure in her role as princess, I hoped she'd be a good mother.
She doesn't have to lose the children altogether. If she lives nearby she can probably see them often. She would just lose custody and not be able to travel with them without Alberts permission.
She will get the freedom to fall in love with someone else, plus the space to find her self-esteem again. The children will benefit from a happy mother rather than a drugged and wasted mom with a permanent miserable look on her face.
I found it very rude of her not to smile genuinely to those receiving the medals, like she couldn't be bothered. But maybe they don't see it because they are so used to her miserable face.