Dear Prudence: Several months ago, my husband turned into an unrecognizable person. He began snapping at me and our kids, then quickly became cruel toward us. He openly began sleeping with a woman half our age. He left our family to be with her, and we have been going through a hellacious divorce.

Not long ago, he discovered that he had a brain tumor, which apparently affected his behavior. He has had the tumor removed and is undergoing chemotherapy. He is also racked with guilt and can see how awfully he behaved; he has shown me true remorse.

He wants to give our marriage another go and has cited the brain tumor as the reason he behaved how he did. Should I give our marriage time, or am I justified in pursuing my divorce?

Prudence says: This is the reason I so often say that when someone has an unusual change in character or personality, a complete physical and mental evaluation is called for.

Of course, the tumor doesn't undo the pain, but it does explain that your husband was not in his right mind. If, no matter what the cause, you are done with your marriage, I don't see how you return to it. If you can get distance from your pain and see that a medical crisis was causing his behavior, perhaps there's hope.

But your kids have been through an awful trauma. Please get counseling for the whole family. You don't have to decide what you want the outcome to be. But having a safe place for all of you to express your pain and fears will allow you to go forward with everyone's best interests in focus.

Send questions to prudence@slate.com.