House construction for an unmarried couple

is a purely private matter and agreement.

Now you got it! And what if someone doesn't want to pay anymore? Then you have a problem! Then you can sue for the money. But the bank doesn't wait for that and suddenly the house is gone if one person alone can't afford it.

If the account is no longer covered, it quickly goes into enforcement.

@perlemann: those who can read clearly have an advantage