Pragmatically, 'husband' is normally used as an inalienable noun. (A table in a paper on "Alienable vs. inalienable possessive constructions" by Martin Haspelmath suggests that 'husband' appears as possessed 74% of the time in numbers based on the British National Corpus, more than any other kinship term listed except 'grandmother'.)
Inalienability is not as strongly marked a category in English as it is in other languages, but "is now a husband" on its own feels somewhat bare. Compare similarly:
? Prince Charles is now a brother-in-law.
? Prince Charles is now a boss.
? Prince Charles is now a neighbor.
If this is all we're communicating, we're more likely to indicate the possessor and say my brother-in-law, the boss of sector 7G, your neighbor, his husband, or rephrase altogether (He was promoted, he got married, he had someone move in next door)
We can make these words alienable if we are talking about the quality of or a change in the relation rather than the fact (He's a bad boss, you're a good husband, he became a father), or if the relation is relevant on its own (I'm a mother now, so I need to...).
In light of that, "Prince Charles is now a husband" is basically only something you'd say by itself if being a husband per se was something he'd been aspiring to.