How do you tell someone to stop interfering?

As you guys may remember, my wife thinks that she's gotta fight every battle her sons get into. They are 26 and 28, roughly. The youngest son is in a good/bad relationship with a girl and they have been going at it for a few years now. Recently he was arrested for his actions and my wife thinks it's all the girl's fault. I have to keep reminding her that her son is just as much at fault than the girl because every time they break up he runs right back to her. And every time he has any little bit of car trouble she'll clock out of her job and go run to his rescue. I'm not clocking out of my job simply because someone has car trouble. And this is becoming a weekly event.

The oldest, as you remember, has a child by a girl and our granddaughter is 6 now. If you remember back at her birthday party in May my step-son and the momma's new boyfriend got into a major brawl at a family fun center which caused him to be arrested again too. Since then the momma has refused to let us see our granddaughter. We've been getting that little girl just about every other weekend since she was about a month or so old. My wife is always butting into their parenting situation too. She will call the girl's momma and bad mouth her to her momma and just won't stay out of their business. I've been telling her for years to leave them alone. He had a baby by the girl so let them figure things out. My step-son has pain not one dime in child support and even though child support and visitation are two separate things they do go hand in hand. If you're paying what you're supposed to in support then the momma probably wouldn't have a problem letting you see the baby. But primarily the momma tells me that because of my step-son's constant arrests and him selling drugs and stuff like that she doesn't want to keep letting her child go with him. I can see her point, however, he is still her father and she shouldn't keep him away from her because of that.

Well, again the wife feels that she is doing her son wrong. Like I said, we've not seen our granddaughter since May when the fight happened. The only way we even get to speak to her is when the other grandmother has her she'll let her call us so we can talk to her for a little while. I'm trying to get in touch with the momma to see if we can start our visits over again because she and I have been fairly cordial towards each other. If I can get her to let us resume our visits with the g-baby how do I get my wife to stay out of their situation? She's one of those fierce momma bears that will always protect and defend her cubs no matter how in the wrong they are. By this point in their lives they have already determined how it gonna go for the next few years unless they both make drastic changes. But my wife can't always just run to their defense anytime they fall down and scratch their knee or get a boo boo. I want my wife to know and understand that it's not her place to keep butting into their lives. Let them figure things out for themselves. People never learn if you're always doing things for them. My relationship with my 6 year old granddaughter is much more important than still trying to raise a 26 and a 28 year old. And I want my wife to understand that too. How do I get her to stop interfering into every aspect of their lives? My wife feels you should always be there for them. If they want to move back home for a while then they should be allowed to. I told her our house does not have a revolving door on it and they were not going to keep running home simply because they have a fight with their girlfriend or get into more legal trouble.