@Moiraroseee I had left the thread as couldn’t see what you wanted.
now I see what is happening. My Q is, if you say you could cover the mortgage payments yourself, why on earth are you allowing to pay towards the mortgage ( it’s is paid from joint account) abd not merely draw up a rental agreement and charge him rent ( from joint account) which you put in a separate account and it is therefore your money and your property remains yours without his money being attached to it?
I appreciate you said you are not an estate planner but I fail to understand this of a higher earner married to another high earner and the owner of property wanting it to be their and their alone both on property deed and in reality.
i guess that’s why you are now on MN needing to untangle yourself.
you never mentioned of he owns a property elsewhere. At the very least, ensure he has his own house by buying another property ( just know being a landlord is not easy, unless you can afford to leave it empty),
it is why women wanting to safeguard their properties are given specific advice ( did you seek it) before they bring a man in their house, no matter how high earning both parties are as you are neatly proving here. That practical advice applies to all women dead set on their asset remaining theirs.
so where was this advice or this search for advice before you moved him into your home?
The only situation that gives more certainty is a contract. Wills, property deeds all can be challenged by anyone with an interest- as you said, he can very well outlive you for 30 years and his circumstances might change ( fallen on hard time).
your kids also sound very young. What are their ages? Does he have kids?