Thinking it’s weird that his 18 year old will have the master room

You've posted already under a different name 'asofcati'.
Only in this post you mentioned that the daughter had the second largest room, the house was brought together after you sold your home and moved in with your two sons. In that post around 8pm last night, you was complaining that her lifestyle is fully funded by her father (your DP) with designer clothes etc and it wasn't fair. She had lost her mother and there was money left over for her. But her dad was still taking care of her and she was working as an apprentice and making 24k.

I'm inclined to believe that you're a made up post, looking for traffic for a certain newspaper. But if you're not, why are you so against his own child. You sound very resentful of her.

You've only answered the person that's agreed with you.

Well this isn’t a good start is it lol. I was ready to be on his side however I think I need to know the terms of your moving in. I assume you are paying the going rent in the area?

You would be really damaging the future relationship with her if the first thing that happens when you move in is you kick her out of her room. And actually all the reasons he says for giving her the master in the first place make perfect sense. Teens do use their bedrooms more (also teen girls would on average have more clothes than their dads!).

Yes maybe if you were starting from scratch you would have the room, but you are not, and given the second bedroom sounds better than many couples' master bedrooms, plus there is storage space elsewhere, how could it possibly be worth the disruption and damage to her first impression of living with you? If you want to 'start from scratch ' in your home you either need to buy a new place together or move in with a man who lives alone.

https://www.mumsnet.com/talk/am_i_being_unreasonable/5195676-dh-is-spoiling-his-adult-daughter

This relationship is going to last two minutes if you move into his place and start throwing your weight about like this, especially if you involve his daughter.

So yes, hang on to your house, because you'll need it.

Teens spend a lot of time
In their rooms. Its where she will study, have friends to sleep over and she probably has more clothes and random stuff than her dad, so it makes total sense for her to have the largest room while he has the second largest and an office.

This was her home first, she's used to her space, you really can't move in and decide to downgrade her. It's beyond rude. You need to remember you're moving into her house, and this is going to be a big adjustment for her anyway. Please think very carefully about any other adjustments you'd like to make, before suggesting them.

It's his house and her room. None of your business.
And as your DP points out, like most teens she will probably live, sleep and study there. You will likely only sleep in your room.
Leave her to have her own space, you have yours.
You sound rather like the grasping step mother on another thread currently running on here.
And people wonder why step parents get a bad press.

@grizzleGrazzle what do you gain by selling yours? Can't you rent it out and then you have some security for the future?

Teenagers/young people spend a lot of time in their rooms. Adults don't tend to. In your situation I really wouldn't make an issue over a slightly larger room and walk in wardrobe. How would you feel if your DS was still at home the shoe was on the other foot and DP was telling you your DS should vacate his room for the two of you?

What are you doing with the proceeds of sale of your house? If it's going into his house, for God's sake make sure you have a proper declaration of trust drawn up determining ownership percentages and own it as tenants in common. Don't put money in unless your name is going on the title.

You're wrong here. You're walking into a family home and trying to boss the DD around. Leave her alone. They have a set up that works fine. Put your clothing in the office or ship on out.

Even though he already explained that it was because teenagers spend a lot of time in their rooms compared to adults and that he has a study as well as his bedroom?

It's a two and a half million pound house. I think the OP will be fine in the second bedroom!

My dc had a desk in their rooms when they were doing their GCSEs and A levels and now one is at university and when she's home she has absolutely mountains of work.

Am surprised an 18 yo girl has been given a large master bedroom. I'd find a man without this odd arrangement; who doesn't let an 18 yo daughter rule the roost or be a princess.

Oh my goodness.

This relationship is a disaster waiting to happen. Hopefully he catches on soon.

Yes, this....

I'm a stepmom who moved in...and yes this isn't a fight I would have had, or even contemplated having. I also wouldn't have sold my house to move in and didn't. I've rented it out and relish the independence that gave me.

Play the long game.

Wow the entitlement that you want to turf a young woman out of her bedroom so you can swoop in and claim it as your own.

You are being VVVVVVVVVVU.

You're moving from your average home into his worth 10x as much abc still making demands .

Id be having second thoughts if I were him

So you haven't even moved in yet and you already have opinions and want to move things around? Hmmmm ... your partner is right to leave the bigger room to his daughter. Also, he has a 2 million home and you had a 250k apartment? Sensing more friction in the future.

You can't move in and kick her out of her room! That's the start of a lot of resentment towards you.
Leave her room well alone or buy a house together and start a fresh.
When we moved in with my now dh his daughter had the en suite ( we had another in our room) but my youngest had a box room, it seemed unfair on the outside as my daughter was there full time and his 8 days a month.
When we mixed that was swapped and both my daughters got the bigger rooms and his the box room but not fair to do in the original home, it would've caused a lot of upset

I trust this is a goady, wind them up and watch them go thread.

On the tiny chance it’s not, you should not move in. You have no understanding that this is her home, and her room is her space. You should not move in and if I were the Father I would have told you the deal is off.

So you want to move in and shove the daughter out the room she's always had?

YABU - no wonder he looked at you like that. It's not like you're in a box room, it's still got an en-suite!

I think before you have moved in you are already sowing the seeds for the end of your relationship.
It's her house too and that's her bedroom . Doesn't matter the size

I think he should run a mile…

What bs. She is not a princess just because she was given a bigger room!!! He explained very reasonably she spends more time in this room, whereas he only sleeps in his and has a separate office space. What's princessy about it???? JEEZZZ