It has taken many many years to see that I have a real problem. So I'm owning this right offf the bat. 

There are HUGE mini wife issues, which SO passes off as me being "jealous". At some stage I'll put some of those issues down on "paper"... this would be cathartic... but, for now, please trust me that the mini wife stuff is there and has been for more than 10 years.

So now SD is an adult (apparently). She's away at University. SO and I are living in different countries for the next three years. This was a necessary move for my work. 

I'm about to sell my house (that SO is living in and that we lived in together for 8 years). He'll rent an apartment and move all of our stuff into it. And then when I'm done working abroad, we'll thinking about buying a place together. 
 

In the meantime, I literally have panic attacks every time it gets close to Summer holidays because I know that SD will try to move in with SO. 

She pretty much refuses to come to the house when I am there. So my view has always been, until you show me and my home some respect, you don't get to move in when I'm away. 

That has always been acceptable to SO because he's embarrassed about SD's behaviour towards me. But now it's not going to be my house. 95% of the contents are mine... stuff I had before SO and I lived together. But the place he rents will be his and I feel like SO and SD will use that to silence me on whether or not she can come live there for extended periods.

I am aware there are really deep-seated resentments there, on my part, for occasions where SO has placed SD's wants over our needs as a couple. And I know a lot of my fears might be irrational. 

But I'm eaten up with the idea of her moving in. Our relationship nosedives whenever she is around. They have no boundaries.I know she's around even before he tells me because his attitude is suddenly hostile where it is usually so loving and demonstrative. It often feels as though, because he's got her there, I become someone who gets in the way and is surplus to requirements. And this is because of their lack of boundaries. 

I can't sleep. I am so full of hate. It's not healthy. I sometimes wonder whether this relationship even has a future when there is so much resentment there. It is a beautiful relationship when his daughter is not around. My relationship with his son is great. My kids get along with SO and SS but they can't stand SD because she has stolen from them and lied about them to SO and causes trouble every time she spends time with us. 

I need to have a conversation with SO about SD moving in. He has agreed with me in the past but I have a feeling that he is going to throw out a big "it's not your house anymore" card. And I don't feel as though I have any objective reasons or rights to even raise the question of his daughter being there other than the house being full of my stuff. Conversations about SD tend to get shut down very aggressively. I get scared to even broach the subject.