We don't give our kids enough credit. They may be young, but they can sense when things are not right. They might not have said anything to you, but they notice the many nights that their dad spent away, how he's hiding out in the bedroom and withdrawing from family activities. It doesn't mean that they know anything or everything, but don't rule out that they're not as clueless as we may think.
Your kids see you every day. They see the loving, caring, engaging, fun mom you are. They can see that you're continuing to invest in your M. When the time is right and they are looking for answers, you can explain in the least blaming way you can.