No, you don't have to speak to her. Your father knows why you aren't speaking, doesn't he? So it shouldn't be a surprise that you won't reconnect with him unless his wife stays out of it. If he wants to talk, he'll talk.
FTR, my dad has not seen or spoken to his grandkids in years (long story). My niece only saw him as a baby and has no memory of him. She's not sad. He isn't sad. It is us kids that are sad about what he is missing. So give your DH a hug and tell him not to worry about it, OK?