After reading this topic I had to think of some wise words my father used to tell me. Sadly we lost him, but he had four daughters and knew how to look out for us.

He used to tell us to never move in with a guy who's not willing to put your name on the lease, because it will make you way too dependent on him. Do not gamble with the roof above your head. If a guy is not willing to give you the security of a house, especially when things go down, he does not care about you and you should not move in with him under any circumstances.

Now back to my advice: - I don't care if it was already his house for a hundred years - I don't care if you don't have a job and can't pay for half the mortgage (you should never pay for a house that's not in your name anyway) - I don't care if a million men will call you a gold digger

You have to protect yourself. If you are in a situation like described, have a good talk with your partner and look carefully how he handles your concerns. He might reveal himself as a LVM.