Overwhelmed with the realization that I will deal with her forever

Yesterday was my MIL’s bday. My husband is really struggling with grief as we near the one year mark of being no contact. I can’t help but feel constantly threatened by my MIL ruining my marriage. It’s like this dark cloud is forever lingering over our family and home. My husband stated last night that he doesn’t want his mother to die and their relationship be in the condition that it is. I understand that we might not be no contact forever. It’s really hard for me to show love/support for what my husband is enduring while also protecting myself and my son/future children. All of this feels so heavy and hopeless sometimes. Any advice/literature for my position in all this? I do not plan on breaking my no contact unless under serious changes or her genuine apology (which is not likely). For context, MIL has serious narc tendencies and is emotionally abusive. My husband sees what’s going on for the most part but is fairly and obviously struggling