Father's day cruelty to her mom 6 21 15

Our ED has don't horrible things for many years - drugs,, alcohol, lies, etc., & even including physical assaults to both her mom & myself. But even worse than this, she at times has tried to use me to try to break my Wife & her mother's heart & spirit, by asking me to have a relationship with ONLY her, excluding her mom, & even once sending me ONLY a Father's Day card that was so excessively nice, it was just plain mean, because she knew it would hurt her mom. After trying for years with this estranged nonsense & manipulative tactics, we sent her an email letter telling her to apologize & knock off her nonsense or to leave us BOTH alone...We've heard nothing from her for nearly a year; and today, Father's Day, & some 7 years or so ago since the last card, she's sent me an email 'Happy Father's Day' wish again. (Her Mom suffered thru Mother's Day as usual with nothing!) We still love our ED for what we know she could have been, but she truly is just mean. It has at certain times caused an unusual strain on our fascinating & loving 45 year marriage, & I hate that she does & did this again! I don't want to let her get away with her cruelty to my wonderful Wife & her Mom! We've already disinherited her, but not told her. Maybe this is the time to let her know this & to also RESEND the email telling her to apologize or knock it off again? But this all still can & does break my heart, especially today, as our only other Son is deceased. Does anyone have any suggestions? I'd appreciate your views & help! This is all so sad & confusing...