My (22M) GF (21F) of 2 years cheated on me

TL;DR: Girlfriend cheated on me and wants me to give her fling a ride home from the airport

My girlfriend and I are both in our last year of university.

Around October / November she ended up hooking up with a guy and fucking him at least twice.

This obviously caused issues, but I think we worked through them.

But….they are in the same cohort and still talk and work together.

Here’s the problem - my girlfriend flies back in for classes this Sunday. The guy she fucked is also flying in.

We live around 4 hours from the airport and transportation sucks. So my GF asked if I can drive the guy back to school with her.

I want to say no, but I feel like this may be petty and rude.

I’m also conflicted because I think it’s pretty messed up that she even asked for it, but I don’t know what to do.

Help….please!?