(((Hugs))) I'm so sorry...
This happens to me when I least expect it. I was celebrating my son's birthday last year. He turned 18. I went to bed with tears in my eyes because my memory of his birth is now tainted with the knowledge that my ex was having an affair while I was pregnant. And the OW even brought me dinner in the hospital, after giving birth.
Their A's change so much in our past .
Maybe you can do what I did and toss the items that remind you of his betrayals. In reality your sanity and emotional well being is far more important than an object.