cushioning
warning
the one-line answer
Maintaining backup romantic options while in a relationship.
Cushioning means you are preparing for a potential fall from your current relationship by keeping cushions. You are keeping romantic backups just in case things go wrong.
mainstream
Your coworker might use this word.
01 / in the wild
hear it move.
warning
he was texting three other people the whole relationship. pure cushioning.
He was maintaining other romantic connections as insurance.