I wrote a massive post but realised it would be the most selfishly long post on Mumsnet. Everyone else summarises really difficult situations, so I should be able to as well.
Right. Astonishingly, this is the short version.
Until last Saturday, my adult (just about to turn 22, 18 when DP and I got together. DP had been very unhappy for years being married and waited for her to safely get her A levels and get her university place. But I must admit that DP left the family for me) SD lived with DP and me in my house. I don't have children: it's just the three of us.
This has been going on for nearly a year, since she finished university at 21, and has been very hard, mainly because - and I completely understand and sympathise with this - she is not nice to me unless she's in a good mood, because she resents me and wishes I didn't exist. So my home doesn't feel like home any more and I've been very unhappy.
She recently announced that she needed to stay with us until September 2017, because that's when her best friend comes down from university and she only wants to live with her (!). Although DP has been in denial about my unhappiness for a long time, he did man up and after an incident of quite spectacular rudeness a couple of weeks ago, agreed that 18 months more of this wasn't possible. We told her last week that she needed to find somewhere by September this year, not next year.
She went nuclear and said some awful, awful things to poor DP and has said she is never spending another night in this house. She is very controlling and gets very angry when she doesn't get her own way. I don't think she means to be or do this: she's been indulged (DP admits this, she is an only child from a very affluent family) and she is young for her age.
So what advice am I actually asking you all for.....?
I think it's: How can DP and I resolve our arguments better? Last night I put my foot down for the first time and said that I was not going to leave my own house just because the SD wants this so she could come back to get some clothes and not have to see me. This ended up with me feeling volcanically angry that I was even asked to do this, and DP feeling angry that I wasn't more appreciative that he manned up and told her it was a no. He gets pissed off when I say "The last six months have been so hard that even a small thing feels like the last straw" because he feels I should let it go and stop hounding him about it, and I get pissed off that I feel I've been walked over for so long.
And: How can we ever recover from this? I really wanted to give her a warm welcome and a lovely home. It's all gone tits up.
And: How does any parent learn how to stand up to their very articulate, very confident, very entitled and very angry child? The things she says go straight to poor DP's heart, she won't stop shouting at him even if he is in tears, and I feel so desperately sorry for him.
I really love DP: he is the love of my life and I only found him late, so I am very grateful for my happiness with him. I am 46. I am totally committed to working hard to make this better. BUT I AM SO ANGRY ABOUT SOME THINGS STILL.
Sorry this is so long.
Desperate for advice. Thank you.