They have to work out what is right for them. But as their child, they more than likely are staying together for you and any other siblings, don't jump to conclusions that as Dad works and Mum "may" stay at home to care for the family that, that is the reason she is staying, as she has no finances.
Sounds as if you are concerned that they may Divorce and hopeful that without financials she may have to stay.
How about giving "both of them" a hug and tell them that you love them. You know living in a loveless marriage sometimes that simple word by someone they love, is something needed.
What ever happens sweet, they are still your parents and will still be there for you.