burn boats
burn (your) boats
[British & Australian, British, American & Australian]
to do something that makes it impossible for you to change your plans and go back to the situation you were in before.
She didn't want to burn her boats by asking for a divorce, so she suggested a trial separation instead.

I'd already burned my bridges with my previous employer by publicly criticizing their products.

[TahlilGaran] English Idioms Dictionary ▲

burn one's boats
{v. phr.} To make a decision that you cannot change; remove or destroy all the ways you can get back out of a place you have got into on purpose; leave yourself no way to escape a position.
Bob was a good wrestler but a poor boxer. He burned his boats by letting Mickey choose how they would fight.

When Dorothy became a nun, she burned her bridges behind her.

[TahlilGaran] English Idioms Dictionary ▲