That was a surprisingly thoughtful reply and I agree with the advice.

I was in nearly the same position many years ago; my deceased partner hadn't been out to his family as polyamorous. When I went to the memorial service, I said I was "a friend". The deception was incredibly hard on top of the grief (and other exacerbating factors). What helped me was leaning on friends I could be out to, journaling, and seeing a good therapist. I hope Needs Help in Massachusetts finds similar resources.