I have been living with my boyfriend for just over 3 years. He has 5 children (two adults who are no longer living at "home")
I meet him shortly after he had separated with his wife and we have been together ever since.
Although he had officially separated and asked for a divorce she has not granted it (according to uk law, 3 years separation both parties have to agree but after 5 years consent of the other party is no longer needed) so we are counting down the remaining months before a divorce can be formalized.

my boyfriend and his estranged wife are english and divorce proceedings will take place in england but i live with my boyfriend in san francisco and his children live with their mother in los angeles where he spends just over half of his time.
she allows him to see the children that live at home (ages 8, 13, 16) every other weekend .. (or every weekend in the rare months she is feeling generous) the children really want to see their father more but they dare not broach the subject with the mother because it upsets her too much

every summer the family (my boyfriend his children their mother) spend a couple months in london. fortunately as i am artist i am able to spend the summers in london with my boyfriend as well.
his adult children go to school in glasgow (ages 21 and 22) but they also come to the london in the summers.

as for adult children- they have meet me, we have spent a good amount of time together. the trajectory has been that they hated me before the meet me, they meet me, we got along some what there was some peace, and then they decided they hated me again. they have threatened violence and have told their father that they forbid him from having a child with me. they have told me on a couple of occasions that they hope my womb is barren. in other words very bratty emotionally unstable girls. i've decided to keep my distance from them now. when we have to occupy the same space i am civil but no longer try to make an effort with them as it just ends up blowing up in my face.

the middle child does not give anyone grief about her father and i's relationship but she refuses to meet me or acknowledge that i exist (is that normal? perhaps so..?)

the youngest two siblings have meet me on only 3 occasions and have from what they have told their siblings and parents and family friends they "really like me" I've been very cautious with them. careful not to push myself on them or try to influence their perception of me.. let them come around to me if the wish too. and they have much to their father's relief have been really sweet . wanted to accept the situation and adapt.

the problem is when their eldest siblings and also their mother most especially hear them recount favorable things about me and the time spent with their father and i they get extremely upset. their mother cannot contain her displeasure . it is a huge source of depression for her and she becomes cold and very distant and this of course worries the children tremendously. it makes them feel guilty about wanting to come to terms with their fathers relationship and new partner

my question is - what the hell i do ?! we have tried are very best to be gracious and sensitive but end of the day the young children are suffering. they are not seeing their father enough and as much as they love their mother they feel victimized by her depression.

has anyone been in a similar situation? the mother hates me hardly communicates with my boyfriend and the adult children antagonize the situation further. what if anything can be done?