Me, My Girlfriend, My Ex and My friend with benefits

So, today the most fun thing happened ever
I was giving my sociology examination ( the examination is a public exam meaningly students from all accross the city give it, different colleges, private candidates etc. )

After the paper, I was met with my girlfriend, whom I obviously knew was going to be there, I was going to drive her home.
Then from behind appears her friend (Before we were dating, she was my friend with benefits)

I wasn't entirely aware that she was going to be there, note that I come from a very conservative society so this kind of thing this whole "fwb" thing isn't really appreciated and is quite frowned upon
She gives me this look, the kind that tells you to act like nothing happened. (My girlfriend doesn't know that she was my friend with benefits uptil now)

So, as we're walking around the tents outside of the examination hall, the most inconvenient thing happens. My ex girlfriend spots me.
(My ex girlfriend and I are still friends, family friends as well, my dad and her dad are friends and that's how we know each other)

> She approaches me
> I introduce her to my old fwb and my current girlfriend
> I introduce my girlfriend as my girlfriend, she decides to introduce herself as my ex
> my fwb gives me this look that says "so you fuckin everyone huh"
> My ex girlfriend says this "Papa ne bola tum mujhe ghar chordogay" (Her dad told her I'd drop her home after her examination, me and her father are on good terms so I can't really say no)
> My fwb automtically sees this (note: my fwb has feelings for me) and invites herself into my car as well

Car Ride
My girlfriend is sitting in the front seat, my ex and fwb in the back
It was as good 30 minute drive, I was with 3 people I've had sexual relations with.
Apparently my current girlfriend knew about me and my old fwb, and decides this is the best time to bring it up
"Isn't weird how you've had a sexual relation with each one of us"
I didn't say anything. I stayed quiet the entire time, while all 3 of them just stared daggers at me the entire time.

TL;DR : I somehow ended up driving my friend with benefits, my girlfriend, and ex girlfriend home all at the same time.