Interesting historical factoid. After Isabella's death, Ferdinand quickly re-married Germaine of Foix. Who was apparently a real looker. Ferdinand was in his 50s when he married the young Germaine and notoriously was always up for bedding her.
A contemporary wrote:
Our [k]ing, if he does not rid himself of his appetites, will soon give his soul to the [C]reator and his body to the earth; he is already in the 63rd year of his life and does not allow his wife to separate from him and she is not enough for him, at least in his desire.
-- from wiki
She outlasted 2 other husbands.