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

And the 18 year old here is at university in London. She is studying to make a decent life for herself and should be encouraged in that. She might well need to live at home after university as housing in London is so expensive. Dad has a 4 bed house, presumably quite a large house, and the 3 of them should be able to live together quite amicably without getting under one another's feet.
What you did with your children isn't what the father here wishes to do. It's his house, he's made a decision and that should be respected. I suspect if we were to hear his opinion now, he might well have an adverse opinion on the OP.
And there is nothing here to say that the daughter has done anything remiss. No bad manners, nothing.

This doesn't sound like a relationship that is going to go well.

So his DD is living at home while at university and using her room to study from... and you fancy a walk-in wardrobe and want to turf her out.

Geez.

How on earth is this going to start well let alone end well?

I can see the logic of your point, but the daughter is having to cope with her dad having a new partner. It won't be a diplomatic move to make her give up her room.

You might be moving in but it’s not your house. Remember that! You have no claim on that house whatsoever but his daughter does. You’re not his wife, you’re not her step mum, you’re just his gf. His daughter is not disposable but you are so you need to get your priorities right and keep your entitlement in check.

Staying as far away as possible as I suspect.

OP hasn't come back.
I wonder if they will.

Well, as long as they are children perhaps; but 18 is not a child.

You can't have it both ways.

You said that 'two adults need more room than an eighteen year old girl' but now she's an adult as well.

Doubt it. Only responded to one post agreeing with her own stance.

@Sheri99

At 18-19 ALL my kids had jobs, were in university (or military service), so busy we rarely crossed paths; as it should be

It's very unusual nowadays for 18/19 year olds to 'rarely cross paths' with their parents tbh.

😂

Your title doesn't match your OP
title says will have
Daughter already has the room
It's her room.

This would totally set things off on the wrong foot - 'Dad moves his girlfriend in and she immediately wants my room'. It is bound to cause ill feeling. It does seem odd that the daughter was given the Master suite but it is too late to change it now.

Put yourself in her shoes.

The earliest this can be changed is when she moves out properly (or goes travelling for a year or something similar)- then you redecorate and move into that room - telling her that she is welcome to use the other en-suite when she stays over.

The OP is giving off evil stepmother vibes.

then you redecorate and move into that room - telling her that she is welcome to use the other en-suite when she stays over

I think you don’t understand the balance of power here. It is not the OP’s house, her BF would have to agree to her redecorating and taking over the room.

If Op wants to call shots over any house she best reconsider keeping her own!

As adults, you and your DP will almost certainly only use the bedroom to sleep in. His DD is a student and I imagine that, like most students, her bedroom is where she studies, relaxes, etc as well as sleeping, so her having the biggest room is not unreasonable.

Where are your own two children going to sleep?

Which two children? OP says she only has one and he has moved out permanently.

OP, I strongly suggest you rent out your home and NOT sell it.
You may well need it.
Rent it out on a rolling 3 month contract so that you will have an exit strategy.

No it’s not weird that he won’t kick his daughter out of her own room for you.
Honestly the expectations some people have are mental!

Which two children? OP says she only has one and he has moved out permanently.

I thought she had two boys, eighteen and at university and sixteen, because that's what she said in her post on Friday.

No, she says she has an only child who has moved out permanently. She's only posted twice.

I largely agree with what you're saying. However, I think asking the daughter to give up her room will just breed resentment. She should never have been given that room in the first place imo but the new girlfriend upsetting the status quo never goes down well.

READ:

OP states she is considering (by inference) that she is bringing 250K into this new household, by possibly selling her house. She is right in estimating this is a better way to do the rearrangement, next step in their relationship; rather than going out and doing all the looking to buy a new home and moving TWO households together, spending realtor fees, moving costs, total upheaval.

Maybe he is divorced. Maybe his 18 year old daughter, living with him in this what sounds like a grand bedroom suite because it is the only way
HE could influence her to not live with her mother, not want an apartment of her own close to uni, thereby avoiding child support or apartment for her costs?

OP: Was this a death or divorce in BF side?

What post on Friday?

And I agree with you, also. Have experienced/watched blended family situations. They are a nightmare and work well depending on so many factors, and don't work, depending on so many factors.

If I were OP:

1. If BF isn't asking for her hand in marriage after four YEARS; and
2. OP offering to sell her home rather than do the upheaval of both of them; and
3. If BF can't see OPs position, as THE woman in his life for four years and possibly his nurse maid in his late life, and her point of view?

I'd keep my home and find a younger man with ZERO kids under his roof who can take care of ME in my old age. We ladies have to plan.

OP has had her kids: she doesn't need his to raise his spoilt daughter.