My only thought is that maybe you should ask your D if she would like to make/buy something for her mom for v-day. Then do it if she wants to. But let her give the gift and just stay out of it after that. I have always done this with my D's and their mom has never had any problem with that. Matter of fact, she has thanked me a few times. With the D being so fresh, your XW may say nothing at all or she may well react like you said. In any event just take it with a grain of salt, no matter. You do the right thing for the right reason.
W 40 Me 40 Blended Family D's 16 & 15 SS 12 & 10 Bomb Dropped 1/11/09 W moved out 1/17/09 with S12/10 D filed 2/23/09