NTA - your daughter no longer has a mother! Also thank goodness she was so responsible and made sure she is able to go to College and live comfortably with the extra money. I am a terminal cancer patient and would be devastated if the money I have put away for my children would be used for my exes step children. It does not matter if she has nothing to go to school. It’s not the child’s responsibility to “share” with said sibling. It’s also a huge red flag that your current partner would even suggest such a thing. It’s not the bio child’s fault in regards to any of this and should not be put in a position to share or have any chance at using said money to start her life - a home, a move for a career someday, investments etc. your partner should be ashamed of herself for even bringing it up. Your step daughter will have to deal with it like 70% plus of most kids and pay her own way through school. If anything maybe she can stay living at home so she doesn’t have to pay rent while in school. Honestly If my partner ever even suggested it let alone acted the way yours is, I would consider leaving them. Money can really bring our a persons true colours. Do you really want to be with someone who has such a gross moral compass? Or have her make your child feel bad about a beautiful gift from her late mother ?