From my perspective, as a Catholic man, the vast majority of intelligent, attractive, poised women are determined to use contraception regardless of whether their husbands agree or not. Now as a Catholic that's unacceptable, but I also consider unacceptable even as a man, for a woman to refuse to conceive by her husband.
So how many choices does the prince really have?
Where is he going to find a woman with the confidence, poise, and respect for the family tradition to be a good duchess, a good wife, and a good mother?