First you need to get legal advice on how your can protect the existing equity in your house and your pension and make sure you understand what CANT be protected. If you marry him, what his rights are if he’s unemployed and dependent on you . Do this without discussing it with him.
Then you need a have a full and frank discussion with your DP about money , how he sees it working if you were to marry, what protections for you both, how much you both would contribute . Do you plan to have kids now - you are only 40 ?
You need to listen hard to what your Parter tells you and write it all down. The aim is to find out what he wants - not to convince him of what you want.
Then once you have all the facts, you can sit down and work out what you want. theres no point in spending time agonising about why you are scared / what it means/ is this normal etc if you don’t have the facts.
Your options are quite simple really . Do you want
to keep things the way they are ?
To marry him?
To split up with him ?
Your sex or gender or his has very little to do with it, unless you plan to have children. It won’t have any bearing on any divorce.
If you decide to keep things the way they are, you should get your solicitor to draw up a cohabitation agreement for you both to sign . He will want to take his own legal advice .