Hi, iam Lola Bollinger, You have yourself a good one!
Why Do Retainers Crack? [Solved]
And don’t let it get too dry – the plastic can crack. To keep it from cracking, soak your retainer when it isn’t in your mouth. Another tip: Don’t bend the wires or your retainer will not fit properly. Be careful when inserting and removing the retainer – and when it’s in your mouth.
Cracked Retainer After Braces or Invisalign: Now What?
What
Cracked, Lost, Broken Braces Retainers - Need to Replace yours?!
Braces 101 – Invisalign / Dental Braces
How to fix your cracked retainer
This is the website I got it from.