Hi Meloni,
I'm pretty new here myself, but as a caregiver, I know that if my dad asked to do chemo alone, I wouldn't be offended. If he asked my mom to let him go alone, she would have a hysterical fit. So, everybody's different....
If you can talk to your MIL and she's not an overly sensitive person, maybe you can tell her that you want to go alone so that you can meditate or listen to meditation CD's. Maybe if you bring such a CD and close your eyes (basically ignoring her), then she will understand. I would say that you should tell her, not ask your husband to do it - so that