I have been dating my boyfriend for 4 years. I am divorced with triplets. I am also a full time student graduating within the year. My boyfriend's daughter use to love me, and she misconstrued something that I wrote her in a text a year and half ago. I have explained it to her, she won't let it go."All i said was "I think it would be nice if your boyfriend pick you up for a date, instead of you always picking him up." Since this event, she won't look at me or speak to me. I have reached out to her 100 times with her response of coldness. She had then moved out of her father's apartment and then we decided to get a house and move in together. As soon as, we signed the lease, she had texted him"Dad, I want to come back for the summer to save money." I had already told my 8 yearold daughter where her room was going to be and so forth. We had to rearrange things so we could accomodate the 19 year old. My 8 year old understood she would not be having her own room. I fixed his daughter's room beautifully. Screen T.V. etc.. She arrived I hugged her and so on. The room remains pretty much empty. She comes and goes as she pleases. She is disrespectful to me "tells me to shut up" she yells at my 8 year old triplets and they are afraid of her. My boyfriend( having 2nd thought about marrying at this point), tells her to stop this irrational behavior,to apologize and she refuses. She says she doesn't care and told us together that she hates me. ( I am crying as I am writng this). I am truly heartbroken. I have done everything other then roll out the red carpet for this young woman. I am a retired model. She tells her father she doesn't like my shorts I wear when her boyfriend comes over. I know she is jealous and feels dethroned. My boyfriend divorced now for 9 years, she was the center of his world. He has over indulged his daughter her whole life. He even states he has created a monster. She has no boundaries and does whatever she likes. She works full-time and goes to school a few credits a semester. She does not contribute anything other then to pay her cell phone bill. My boyfriend pays for everything.. car $600.00 a month. Theses last 2 incidents were pretty hard on me.. I asked him to give her consequences for this kind of behavior i.e take her car away for a week. He says he can't do that. He feels he will lose her forever, what he doesn't realize is his daughter will move on with her own life someday and the one he will be losing is me. My questions is , I know my boyfriend is the one that has to change his behavior in order for anything to happen.. I have seen a little progress, I don't feel as though I am on the last rung of the ladder, However, how do I cope with this?

If she originally wanted to stay for the summer, why is she still there.

She works full time, why can't she pay her own way, in her own place.

She has effectively planted a wedge between you and your fiancé, and your fiancé is not putting his foot down, and it seems there are no consequences to her very bad and disrespectful behaviour toward you, and the triplets.

When you and your fiancé moved into your new home, she was not living with you at the time. I see this as your home equally to your fiance's home, you have 50% of the say in what goes on.

I would be taking my 50% and telling him to take himself and his 50% out the door with his daughter and set up house somewhere else.

The 19 year old has to resume her independent life elsewhere. She is only a guest in your home, and you should not be expected to put up with her.

How much rent does she pay?

Sounds like you and hubby to be needs to have a talk, he needs to set some rules for her, or I think I would have the second thougts and be looking to move out

You definitely shouuld approach the talk with him first. Take him away from the situation and let him know that you are not asking him to choose but that the situation is harming your much younger children who have to live there. Suggest that he initiate a conversation between the three of you and have goals written down hat you wish to accomplish during this talk. Communication should be a requirement between family members.
Also, put your foot down to disrespectful behavior and ask him to do the same. If she cannot express herself in an adult manner while she is at home, then she should not be there. Ask him to start with addressing her tone and making her explain in a calm manner her concerns instead of shouting. Be open to criticisms that she has as well. Surely he can see the benefit of having a family meeting.
If this does not work, you should not ask his approval to punish her in your house. Let him know that your feelings are concerns are valid and that you will always act fairly. A conversation at lthe very east should be mandated by her father.
Lastly, know that she is most likely a scared and hurt little girl trying to lash out and keep from sharing him. Stop trying so hard. It is just giving her more opportunities to put you down. She does not have to like you, just respect you. If she can't say anything nicely, than she should not say anything at all.

She pays zero in rent.

Thank you so much. I will do that. You are right she is a little scared hurt girl.