What's your criteria for introducing the new person to your kids? How about introducing their kids to your kids?
As far as timelines go, I think trying to arbitrarily define an interval is absurd: Someone could be ready in a day, while others may take years... It's like trying to define a "proper" period of mourning: Some people would happily dance on their deceased partner's grave while others will never get over it.
BUT...
I am curious about the kids angle. As some of y'all know I am a single (ONLY!) parent with both of my teens 100% of the time. I've always held that interaction with my kids is critical: If a potential partner doesn't like my kids, or my kids don't like the potential partner, it's off. No question, no hesitation, no regrets: Done. So, I've never been shy about introducing potential mates to my goobers.
The way I look at it, the largest part of "potential" in a relationship is my kids because they come first, so there's no point in exploring any other potential if a good relationship with my kids is a no-go.
I do realize, though, that 99.999988734% of the people out there think about this another way, and prefer to explore potential before involving the kids.
Needless to say, I'm following this topic with interest.
Cheers!
Gary