every Jack has his Jill

For every man, there is a woman who is ideally suited to be his romantic partner.

"Jack and Jill" (sometimes "Jack and Gill", particularly in earlier versions) is a traditional English nursery rhyme.

The phrase "Jack and Jill" existed earlier in England to indicate a boy and girl as a generic pair. It is so used, for example, in the proverb "Every Jack (shall/must) have his Jill", to which there are references in two plays by William Shakespeare dating from the 1590s.