Give her an ultimatum.
Wait...
First you need to assess how much you really care about those kids. If you really don't care about them, you need to give her a deadline when she needs to move out.
If you really do love those kids, you have to remember you need to love & respect yourself. SO...
The ultimatum needs to be articulated in a way where SHE has to examine how good you've been treating HER family. She should think hard on that. And if after thinking about that she still feels that you need to take a lesser role in the life of the children who you shelter, she needs to make arrangements to leave. All the while, you need to let those children know how much you care about the & how much you want them to stay but things happen.
That way they don't have a vendetta against you & it doesn't affect how they treat relationships later on in life.
Breh, realize that you are the most important person in your life.