Commitment issues

[Housingcraze]

MY partner owns family business which is 4/5 property's he is Landlord - has own property which is paid for, shares ownership with his sibling,

i have own property from uncle inheritance was only niece, say mine worth 150k - money isnt the issue,

We been living together for 18 months now and both rent out our property's - and rent a flat together, to see if we were going to be compatible, i had bad previous Rls and wanted to make sure, rather than buy somewhere and lose some of my money. He was more than happy to do this, knowing this!

Now we ready to move in together in my mind, putting our finances together and both selling our places and getting our own place so i thought this was normal for couples - to put their stuff together to buy own place

his version is to still rent his place out and get mortgage to buy a place together but this means paying a mortgage and a get out clause if it goes wrong - whereas we could be mortgage free and i not bothered that i will be putting more in so to say, he was adamant he couldn't do this and wouldn't do this, and even said why don't we sell your place and i take the mortgage out to get a bigger place, doesn't feel like he committing tbh or given 100% he got a get out clause!
I am fine to be told i am unreasonable

AIBU to ask him to sell his share of the property to the sibling?

You say the properties are in a 'family business' - it probably depends on how that is set up.

So:

1. Maybe he doesn't want to get rid of a quarter of the family business by selling off the house externally, and his sibling wouldn't/couldn't buy it out, for example because the business requires them to have equal shares of all the properties and be equal partners.
2. If he got a mortgage to match your input from selling your flat and you stayed unmarried, that would be fair (although you'd lose some of your personal stability of being a sole owner). But, if you marry, you become partly liable for the mortgage - and would you also become part-owner of all his business properties or are they (as I suspect may be the case) fenced off as belonging to the business in a trust or separate entity? If the business properties wouldn't become a marital asset but the mortgage debt would then he is BVU to suggest that deal for you.

I suspect the sibling could buy my partner share, or could refuse for any type of reason for his own stability.

I kinda know he being youngest child gets less percentage of the business, i think its (guessing) sibling gets 60% he gets 40%. when it going through probate, i was concerned why didn't either of them, argue this and get equal shares?

I suspect the same, if we did get married i wouldn't get a thing, they would go to siblings child, and yet i would be liable for part of the mortgage which isn't what i would wish for. Im pretty sure sibling partner has a prenup also which i find bit concerning tbh, forget the money side of things, i would see that as mistrust completely in his partner yet again it would go to the child, where does that leave his partner.

Sibling pays VAT so must be earning, as he deals all of the business stuff property development and so on. my partner pretty much just signs paperwork if i honest.