Usually I can snap my mom's delusions away but lately she is trying to convince us of them & truly is concerned and paranoid. Actually thought I had someone else in my bed other than my husba nd which made her very upset. Trying to dismiss it made it worse. Other times she thinks there is another portal that she visits at night...talks excessively about these delusions. I think I'm losing my mind! How do we deal with it without screaming at her?
As for your reaction, I guess I'd try the generally recommended approach of validating her feelings, acknowledging her reality, and trying to distract her. This is much easier when the hallucinations are benign than when they are disturbing! You are certainly not going to say "yes, Mother, you are right. I was sleeping with another man." But maybe something along the lines of "Oh, Mom, you poor dear. I can certainly understand how upsetting it would be for you to see another man in my bed. I don't blame you at all for crying. I've got to tell you that I love Hubby very much, and even if I didn't I would not have another man in my bed while I'm married. I am so sorry you thought you saw someone else. It must have been a trick of the light. The only man in my bed is Hubby."
Sometimes my husband's hallucinations involved dead bodies or other topics I would find disturbing but he was not disturbed by them. In that case it was easy to go along with them. "OK, I'll stay out of the bedroom until the crime scene investigators get here. Should we play a hand of cribbage while we are waiting?" I didn't have to deal (so far) with the hard ones that distub the person having them. My heart goes out to you. I hope that Mom's doctor may be able to come up with something that will provide a little relief.