My SD was/is the same way. It was getting really bad during our last vacation as she would not let go of her dad's hand while we walked two miles where we wanted to go and she kept trying to get her dad not to hold my hand. She would also sit on the same side next to him. After the vacation, I finally just snapped and explained to DBF on what mini wife syndrom was, and just laid everything out, calmly and he listened. Ever since then, I don't want to speak too soon, for the past month and a half, there has been no cuddling on the couch, or handholding. Though she still kisses him on the lips before she goes to bed or leaves to go back to her moms. It is a working process and I do make comments saying, "Isn't she a little old for this and that," kind of seems to help. I also keep SD12 pretty busy while she is at our house so doesn't really have the option to lay on DBF. She does still sit across the dinner table and just stare at DBF like she is in love with him and it drives me crazy... but being on this site will definitely give a lot of good advice. Like I said, it's a working process. 

your SDs behavior will only get worse, especially if you get married. Can you imagine what you go through on weekends now becoming a daily impact????

Your SO is hinting at marriage. Perfect opportunity to bring up your concerns yet again and head to a counselor. Your DH is not doing his child any favors. And really, you are in competition with her and HE is causing it. 

I deal with a MW. She caused so much trouble in our marriage, to the point we almost divorced. She was in her 20's when DH and I met/married. Over time, DH addressed the issues and either toned them down or completely stopped (like the walking with arms locked in the mall..eww). I've also had instances where wait staff wasn't sure who was with who due to her inappropriate behaviors. After 12 years, I'm completelydisengaged from DH's kids; way too much drama and trouble for my life. 

So, again, I strongly suggest counseling to address this issue. Make sure to "interview" your therapist to know if he/she has experience in the High Conflict Step world, and Mini Wife Syndrome. There is a lot to unwrap here and not every therapist is qualified to work in this area. Good luck.

This is on your SO. Personally, if he was acting all cuddy with SD, especially to the point someone mistook them for a couple I would leave - the room, the restaraunt, etc. I wouldn't play third wheel to anyone & I wouldn't want to be associated with the pervert cradle robber - which is the judgement people around him are making (unless they deal with a miniwife). Why do you tolerate it? 

Do not move in or marry this guy UNLESS he creates strong appropriate boundaries with SD. Honestly I doubt that he will, thats my negativity showing. 

If you marry this man I will bet the pig pen SD will amp up the clingy behavior. She has been the wife/daughter for many years. The center of attention. Dang NFW will  she want want to give it up. Your SO's guilt wont let him either. You will constantly feel second place . Your insecurities that you have already will also be amplified.

I was married to a man with a mini wife. It breaks the heart, takes away self esteem. I never ever felt good, attractive or special because SD was lurking in the shadows as the other woman type behavior.

Date if you want with him, but dont move in. You will NEVER be the queen of the castle. If it is difficult now and you dont live with him, just wait til you do. Your life will never be peaceful.  But even dating him look at all the insecurities you have with this. Any woman would. Life is to short to live like this.

 echo the others - if things are bad now, in the "honeymoon phase", they will only get worse over time.

From how you described things, your SO doesnt want to change things. Youve told him how you feel, what you think, what is wrong and he shoots you down each time. He is enjoying the attention from SD. He is getting his emotional needs met and the women in his life are competing for his attention. He will not want to change this very dysfunctional dynamic. Because he doesnt want it to change, you can diagram, do therapy, buy the books, underline the passages, bookmark, video tape all you want.

Hes not seeing the truth, because he doesnt want to change. So, his technique is to push everything back on you. I used to hear the same trope "your jealous of a CHILD". And then I explained things, and it got nasty. But things changed. SD no longer pushes herself in between us like she did as a child. She no longer gets in between us when I hug my DH. Its been long enough and Ive done enough, that he cannot say I dont love his child, so I just make everything about her "best interest".

You can try that one, sometimes that gets changes happening. Its in her best interest long term, for her to individuate herself from the family unit, and it will be better for her relationships if she acts like the child and not the wife. Plus, you will have to excuse yourself because its not in your best interest to be the side-woman. Although that point may not make a difference.

This SD will have a very rude awakening when she goes out into the world and no one worships her.

This girl is in her late 20s and still tries to hold daddy's hand or put his arm around her. It creeps me out and it hasn't gotten better. She's been creeping me out since she was in her mid-teens. I'm an SD on both sides and have NEVER behaved this way with my SPs. I totally respect and am happy for both my my Bparents. SD continues to be enabled by her limited sized family and can't get her #!#! together, hmmmm... I wonder why?! 

Anniebear1115, it is so unfortunate you are going through this with your significant other. Some of the members of this board give really great advice. They really helped put things in perspective when I  was in a relationship with a man, who hid the fact he had a mini-wife and other issues that if I knew the. truth, I would have never dated him. Leaving him was one of the best decisions I ever made.

You said 

I have been in a relationship with my SO for 4.5 years now and we took things really slow and didnt involve the children for almost 2 years because we wanted to make sure it was going to work before introducing them. 

If you don't mind me asking, are you in your late 20s or early 30s? Do you want to get married or have more kids? If so, why are you wasting precious years of your life on this selfish and emotionally unavailable man? He is willing to hurt you, your son, and even his own son so he can carry on this dysfunctional relationship with his daughter. Even if you two got married and had kids, all that would fo is create more hurt people. Why would you be interested in a man who has this type of dysfunctional relationship with his daughter? You have already wasted 4.5 years of your life on him. Why waste anymore?

You said

He is now hinting at marriage and possibly moving in together and I dont know how to stop feeling like this.

Hinting at marriage and moving in together?? Sounds like he is just stringing you along. Why would you want to marry a man who doesn't love you and respect you as his partner?  If you marry him or even move in with him with the level of disrespect he already has for you, can't you see things will only get worse? You are settling yourself up for a lifetime of heartache if you stay with this guy.

You said

He refuses to see anything wrong with his little girl and a lot of the time I feel that it is because it is his last baby (even though she is not a baby anymore) and he refuses to see that she is a young woman now and not a little girl. He gets very denfensive and shuts down any time I bring up anything regarding her. He doesnt make her do any chores, doesnt correct any of her behavior and lets her get away with ten times more then he lets my SS or my son get away with. 

Why would you allow this guy to make YOUR minor son feel "less than," all so he can put his daughter on a pedestal? That is extremely damaging. Do you defend your son, when this occurs?  Your significant gets defensive or shuts down when you try to bring up anything regarding his daughter. That is quite manipulative. He knows he is wrong, but that is his way of letting you know he doesn't plan on changing anything. It is not about you being jealous or insecure, it's about him blatantly disrespecting you. If he wasn't ready for a healthy adult relationship, then he shouldn't date or be in a relationship with you or any other woman. He doesn't get a pass to act like "less than" a man just because his daughter's mom passed when she was young. Didn't he know that prior to meeting you??? As sad as it may be that his daughter's mom passed when she was young, I wouldn't allow someone to come into my life and treat me "less than" for any reason and especially not because of something that occurred prior to meeting me.  I also wouldn't be going to couples therapy/counseling for this. This is THEIR problem, not yours. If your significant other wanted a healthy relationship with his daughter, he had 12 years since the time her mom passed to go to therapy/counseling and make changes. He hasn't done that. He obviously can't teach her what's appropriate behavior for a young lady. If he truly loved you,  respected you, and trusted you, he would allow you to put those much needed boundaries in place and work with you on them. He isn't doing that, and unfortunately I just don't see this turning out well for you.

Next time he hints about marriage, tell him that he already has a wife. Then, when he protests, ask him who sits beside him in restaurants? Who holds his had all the time. Who gives him constant kisses? Who etc.etc.etc. with all of the things that she does that he should be doing with you. You're not jealous, you just want your rightful place as his partner, not as his daughter's (almost) equal. Maybe also be blunt and ask him what people think of them when they see them together, 1. he's a pedophile, 2. h's growing his own, 3. she's jailbait. Photos of them together could illustrate this because he probably doesn't realize how bad things are.

So my SD12 has/had mini wife syndrome excessively. Constantly wanting to lay on her dad and cuddle with him, would stroke his face and look at him like she was in love with him, she needed to hold his hand anywhere we went, she needed to sit with him when we would go out to eat, she felt that she had control over what is hung on the wall at our house, and what goes where in the kitchen, it was bad up until recently. 

I had hit my breaking point and just expressed to my DBF of how I felt and what mini wife syndrome was and what a disney dad was, and how it looked and that he knows that our daughters are only a year apart in age. I expressed how I felt like I was the other woman, and all of this I expressed super calmly and he gave me back calm responses. He said it was because he still see's his daughter as his little girl. Well, we ended the conversation and ever since then things started to change. We just had another discussion about it on our mini vacation and I was like, "Look, she's going to be a teenager in just a couple of months, a teenager..." And he just made this shocked looked and he then said, "Wow, you're right. and I have put a stop to kissing on the lips and cuddling and will continue to." 

Sometimes just having a sit down often until you start to see a change really does help. It is HIS job to put a stop to her behaviors, not yours. But you have to I guess, "wake him up" open his eyes and like winterglow said, take pictures and then show him, it may do the trick... or having other's witness it as well.