I'm a home owner and have had a mortgage alone for 20 yrs. 11 yrs ago I made a will leaving all my property and assets to my biological daughter. For the past 10 yrs I have lived with my partner but have continued to pay my mortgage alone and mortgage remains in my name only. We are due to marry next year and my partner has 4 grown up children.thouugh I love them dearly I wondered if anyone could advise me regarding this matter as I worry that if I was to die though I would be happy to provide some money for each of them I don't want my own biological daughter to miss out on what I have always considered to be her inheritance.

ANY question on law needs to include your general locale as laws vary by area.

I would suggest that you consult a local attorney to prepare both a prenup and make sure your will is ironclad.

Agreed, his rights to joint property differs greatly on where you are at. How the property is deeded and so much more.
You will need a good attorney at this point to work out the details before you get married. To ensure it happens according to your wishes

As others have said, you need to update your will upon your marriage. Your husband could, if you die before him, possibly have the will disallowed if if doesn't specifically provide for him. And, absent the will, he would have a substantial share in your estate. His children, on the other hand, would usually inherit nothing.