hayfmr.....sounds like they may be angry at you for staying and keeping them in the situation....(among other things)....Or, if you are Co-Dependent...they may have copied your example, also...toward their mother....
Alcoholism has a profound effect on everyone in the family....especially, the children, as they are developing. And, every child is an individual.....
Lots of possible dynamics, here, I think....
You may be able to gain more understanding by getting and reading the book and materials of Adult Children of Alcoholics. You can get these materials from amazon.com
Your girls are, of course, Adult Children of Alcoholic....and, could benefit from the materials...though they would probably be resistant to anything that you asked them to read, at this point...due to the anger that they, obviously have...
I have seen lots of adult children and lots of older...teen children, become resentful when one divorced parent takes on a new partner....even when addiction was not an issue....This seems to trigger a lot of emotions in the children.....
this is complicated stuff and very painful for a family....If I were in your shoes, I would certainly get some professional advice....and support, on how to handle this....
Have you sought any kind of help?