step-whipped

When your friend is totally whipped by his girl, yet it somehow affects you.

YOU: "Bro, let's go get some Chipotle."

BRO: "Yeah! I love Chipotle! Can Mandy come?"

YOU: "Yeah, sure. I guess."

BRO: "Mandy doesn't like Chipotle. She wants KFC, so let's go there instead."

YOU: (To yourself) "Dang. I'm step-whipped."