But just imagine how "clairvoyant" a person would have appeared who feared for Charles' and Diana's marriage even before they were wed.... Or think of the Schaumburg-Lippe/Sayn-marriage who ended after the heir was born and then the Fuerst Alexander moved on to marry a commoner (Nadja), whose children have no right of inheritance....Or the Oettingen-Spielberg/Sayn-marriage which broke down after the heirs were born and ended in divorce...
These things happen, especially in Germany and I must say I much prefer the Habsburg-approach of today where not a past head of the family but the present one decides about who is equal or not (if these families still feel the need to have equal marriages....)