1 divided by 2 equals two halves?

7 For this cause shall a man leave his father and mother, and cleave to his wife;
8 And they twain shall be one flesh: so then they are no more twain, but one flesh.
9 What therefore God hath joined together, let not man put asunder.

What happens one spouse dies? Are they no longer joined as one flesh and are now two separate singles?

1 divided by 2 equals two halves: While alive they were one flesh, in harmony. One dies,
the harmony is gone

A spouse cannot be joined to a dead person, therefore yes, the remaining spouse must be now single. Like Ruth.