I bought an oximeter to have in the house to check our values...should we get covid. my spo2 readings are between 97 - 99. my spo2 husbands readings are between 88 - 92. should we be worried that his is so low?

Pulse ox: "Normal arterial oxygen is approximately 75 to 100 millimeters of mercury (mm Hg). Values under 60 mm Hg usually indicate the need for supplemental oxygen. Normal pulse oximeter readings usually range from 95 to 100 percent. Values under 90 percent are considered low." REF: https://www.mayoclinic.org/symptoms/hypoxemia/basics/definition/sym-20050930

Normal/low: Values are normal for you and low for your husband. Without circumstances for why checking, symptoms and so on, hard to comment. it might be wise to let your husband's doc know about readings.