Hello!  I have spent a lot of time reading through a lot of your posts and I'm so relieved I am not alone. 

My BF and I have lived together for 3 years.  He has a 28 year old daughter who is a FTL.  She is extremely spoiled, entitled and babied. She literally does nothing (no work, no school, no responsibilities.) Everything is paid for. She lives with her mother. Mommy pays for the car, insurance, exotic pets, plastic surgeries if the girls demands it.  The girl will throw tantrums and start throwing things in her room if the mom brings home mustard instead of mayonnaise for her sandwiches, for example. This is a 28 year old. All three of them have baby names for each other: daddy and mama and her baby name I won't say. It's just gross.

All bad choices have had no consequences whatsoever. Mommy and daddy have always swopped in and "handled" whatever mess she makes in life.

The girl is so self absorbed and me-me-me - after her dad had surgery, she couldn't even bother to text him or me to check in and see how he was doing. Couldn't bother to reach out to me to ask if she could run to the store for us or help in any way. An entire week went by and she didn't reach out. All on a cell phone daddy pays for. Oh and she lives about 4 miles from us. 

When her dad's birthday came around, I could see the hurt in his eyes around 3pm or so.  She couldn't be bothered to wish him a happy birthday.  HE actually finally reached out to HER when it got later in the day and asked her how she was doing and then had to tell her he was a year older that day. 

"Daddy" will twist this around and say "I heard from "D" and she wished me a happy birthday!!"  (when the truth is that he had to reach out first.)  Back when he had his surgery, I asked him "have you heard from "D" at all?" He will twist the answer by saying "yes, I have heard from her a couple of times."  When the reality is, she only responded to him reaching out to her to let her know he was doing ok. 

She just does not give-a-s***!

My problem?  Daddy thinks baby is the sweetest, most precious, wonderful thing. He just doesn't see what a manipulative, narcissistic, spoiled, entitled little B she is.  The denial is crazy - especially when it's right in his face. He just doesn't (or won't) see it. 

My daughter (30) lives out of state with her husband and they ordered and shipped BF some of his favorite choclate chip cookies and called him to wish him a happy bday. His lazy, spoiled brat lives 10 minutes from us and couldn't be bothered to even text her own father. 

And he doesn't see any of it. He still runs around spoling her, paying her bills, running her to appointments.  Both mommy and daddy do this. 

He will allow bills to pile up over here, if baby needs something first instead.(gas or cigarette money, oil change for the car, food for the exotic pets, etc.)

He wants to get married. I say no.  If our marriage and I can't come first, I will not go down that road.

So, I have decided to disengage. I don't ask, I don't care.

The truth is, I wish this person didn't exist. She is a drain on society and her parents and formerly me.  Her mother's husband (2nd) finally had enough and ended the marriage.  I spoke to him and he told me how bad it was.  He explained that this has only gotten worse over the years.  The mother put spoiling and enabling the daughter over her husband and their marriage. The girl runs the show; she runs her parents' lives. And they gladly run around like headless chickens to please her and cater to her every whim and want.  

The girl and I do not like each other.  Me - for the reasons above and her - because daddy has someone taking attention away from her. And also because since I came into the picture, he has tried to lay the law down with her (somewhat) and she knows that is coming from me and not him. Because, before I came around, he never said some of these things to her before. She just got whatever she wanted when she wanted it. But I have given up the fight. So now, we are back to the way it was. I stopped opining on her or the situation, so he is back to falling over himself to spoil her. 

I see her dad is/was torn, so I encourage him to go over there and spend time with her as much as he wants. I don't want her in my house. I can't stand her.

Dad has realized my new attitude towards all of this and tries very hard to convince me that his sweetheart is so wonderful. He just doesn't see the reality. I stopped trying to explain it to him or point out examples of how this just isn't true. He just cannot see the manipulative, narcissist she is.

So, I am now disengaged.  Whenever the text or calls come with more drama (from her or the mom), I leave the room and when I return, I will ask him what he wants for dinner. In other words, I don't ask questions anymore. I don't want to know what the latest drama is. I just. Don't. Care.

The only time I do care is when it effects something we are doing - plans, etc.  The girl loves to throw (or try to throw) a wrench in our plans.  He will drop our plans and run to her with whatever her drama du jour is.  When this happens now, I just continue with the plans we had. Alone.

We also have a business together that, with work can really take off. I now won't even discuss doing this.  Why?  Because I know that if baby calls, he will leave me with the extra work and run to her (this has already happened many times) and  I am not going to put myself in this postion anymore. Do I tell him any of this, you ask?  I have tried and the second we start talking about her (and if I dare say anything remotely negative) he gets ultra-defensive and the conversation stops right there. You just can't say anything about his precious sweetheart.

When he brings up growing the business or marriage, I just slowly move the conversation to a different subject.

I guess my first question is this:  Can a marriage or even a relatioship work if you cannot stand his adult kid or kids? I mean, should I just cut my losses now knowing this road just ends at a dead-end? Can this ever change? When it's just he and I, things are great. No problems.

My other question for those who have decided to disengage, did that work in the long term?