Most of the people are born with a soulmate counter on their wrists.
It is a number defining the number of days they’ll meet their soulmates in.
It is initially black and glows white when the number drops to zero, indicating that their soulmate is finally there.
Some people have a red mark and it glows red on finding them.
The red mark is an indication of a person who will bring more trouble than good to their lives and that they would rather stay away from them.
On the demise of their soulmate, the mark becomes a couple of Xs.