@jespah,
I agree with you 100% jes as far as assessing the situation (except that I believe he's buying into this next house, and he and his friend haven't wanted to include her in the deal....very telling right there.
I think we're saying a lot of the same things, me just believing it's already more of a done deal.
As far as him making an ultimatum, he hasn't presented terms, made demands, even said "take it or leave it" From what we know (and I'm really trying to stick to only what we know) He's been clear in his actions. He knows what he wants to do, and is going to do it. End of subject. He asked her if she plans to come along. That's up to her. From what the OP has written, he hasn't even said he would like that if that's what she chooses.
It that all means this was a relationship of convenience to him, that it meant someone to sleep with, as well as contribute to the rent, fine. The tone of the whole thing is "I'm buying a house with friend (be on the mortgage), what are you plans" That's not an ultimatum. We don't know if he even wants a girlfriend, or a relationship, or anything beyond that he definately wants to, and is going to, invest in a house with a friend.
The OP is the one tied up with what she thinks "should" be happening at this point. Maybe she's a Life Scripter. The "first comes love, then comes...."
It's really reading a lot into it getting into the "maybe she wants space for kids" or this that or the other.
She can have whatever she wants. It just might not be with him.
He's a free agent. He's said "I'm buying a house in this area. Are you planning on moving with us?"
It's on her to decide what she wants to do, not to try to change him into what she believes he "should" be at this time.
For what it's worth, I've been in the position of that girl, and when I look back on it, I have to wonder "What was I thinking?"
I've also been in the situation where I've been in the situation of the guy. Not necessarily in a romantic, but another equally important relationship, and having someone communicating in some way what I "should" be at a certain point.
A lot of what I should do, what was expected, what would make everyone happy, etc.
I learned I had the power, not over others, but for myself, to not get dragged into the sea of what/how others thought. But calmly just proceeded on with my plans.
From the way/what this woman has said, she's got a bunch of different scenerios all running around on what she'd like. He seems like he's directed towards what is best for him.
So far, the concensus seems to be that this guy should get himself involved in her issue of what she thinks he should do. I imagine it's infuriating thinking he might not play along with what anyone else wants.