drive a wedge between (someone or something)

To cause discord between two people or things. I used to be close friends with Tiffany, but once she started dating my ex-boyfriend, it really drove a wedge between us. No, I don't see my parents much. There's just a ton of issues that have driven a wedge between us over the years. I would never say something like that about you! Al just wants to drive a wedge between us—don't listen to him!

drive a wedge between A and B

make two people become less friendly or loving towards each other: The disagreements over money finally drove a wedge between them, and they ended up getting divorced.

A wedge is a piece of wood, metal, etc. with one thick end and one thin pointed end that you use to keep two things apart or to split wood or rock.