Hello and Thank you for using Just Answer. I am sorry to hear that the parents are separating. The two boys may be sad and even become depressed if divorce is in the future. They may also attach to one parent more and worry about who they will ultimately live with.
Your message sums up everything perfectly. The boys however will wonder about exactly what kind of adult problems that you are referring to. You must be ready to offer them some type of general explanation rather than...you do not need to know.
You may also want to seek family therapy while your family is going through this transition. The boys may be more willing to release their emotions to a more neutral source.
If you need more advice, just ask.