Recently married DH who has been divorced 5 years and has 1 daughter from that marriage (6 yo). Their marriage broke down shortly after she was born (nothing to do with me). They were successfully co-parenting until I came along (keys to each others' houses, 50/50 split in childcare, lived nearby, had child-related outings together). However, since I came on the scene and we moved in together to another town with my two DSs things have become increasingly strained as DH is no longer on tap for her every need. She has been bombarding DH with emotional letters grieving their loss of friendship, wanting him to take her to dinner to discuss DSD, constantly phoning/emailing him at work to discuss haircuts and underwear. She completely blames my existence for the change in her status quo: in her words "there's room for other people but we three are the real family and will be together for the big milestones". I have met and she is perfectly civil to me but refuses to discuss any child issues with me. She does not receive alimony but we pay for all her costs (school, sports). When we moved house DSD came home one the first weekend with some new duvet covers plus an invoice to be reimbursed ffs. Anyway rant over as there are many incidents I could cite. Try to take them all in our stride but the latest discover is that she has suddenly started using DH's name - having never changed it when they married or during her marriage. We found out by accident and she first denied it although quickly afterwards admitted it saying it was purely a work name. Now I think there is more to it than that and am livid. DH says (and is right) that he can't stop her as she has the right to do so but I feel she is asserting some warped type of possession of Should I take the high road again?