I own my property solely, and my current will leaves everything to my nieces and nephews, if I marry my partner who has three children from his 1st marriage, how do I protect my nieces and nephews inheritance. I believe he would have no issue more worried about his children.
Once you marry your current will becomes invalid. You cannot disinherit a spouse. So he's entitled to a legal right share. His children would have no rights as they are unrelated to you.