My daughter passed away in a tragic accident when she was 2 years old. At the time my step daughter was still coming around regularly and we had a decent relationship, we weren't close or anything but I tried my best to get along for my husband's sake. She was 13 at the time my daughter passed away and SDs mother came to my husband and I asking if she could have some of my daughters ashes to put in a keepsake for SD. I refused off the bat. Not only is SD not responsible enough for something that important, I didn't like the idea of separating my babies ashes at all. SD has since stopped visiting as much and it's been 3 years since my daughter passed away and SDs mom came to me again asking for "more ashes" because SD lost the keepsake sometime ago and was torn up about it. I was shaking because I was clear about not wanting to separate her ashes and asked her what she meant. She told me that after the initial conversation we had 3 years ago, my husband gave her the ashes anyways to put in the keepsake. I confronted my husband on this and he shrugged it off saying that it wasn't that big of a deal. I packed my bags and took my daughters urn and went to stay at my sister's house. It's been 2 weeks since I left and he's been blowing up my phone with phone calls and texts, some begging and crying and some telling me I'm an ah for blowing this out of proportion. Then today a mutual friend sent me a screenshot of a post made on Facebook from SDs mother saying that I am punishing my husband for doing something nice for his only living child and that I am just bitter. I am so torn up over this... AITAH?

Eta: I should clarify during the initial conversation I never said I wasn't open to having this conversation again at a later time once she was older and more mature. When discussing arrangements for our daughter we agreed mutually that she would be cremated ONLY because neither of us knew where our final resting places would be and we wanted her with us wherever we ended up, not buried just to be buried. We are both from different states than we are currently residing in so neither were sure we wanted to be buried here.