Mrs. Herron 2 [COMPLETE]

The incident

Mrs. Herron book two chapter one:
Let's get back to the part where Zach proposed to you and you said yes, alright?
To celebrate, you and Zach went to a nightclub and Zach told you he was going to get you a drink.
Half an hour passes and he still hasn't come back to you, so you look for him.
After 20 more minutes searching for him, you finally see him. Making out with a girl.
*Your pov*
It's been half an hour now and Zach still hasn't come back. He told me he was going to get me a drink. I spend twenty more minutes searching for him and I finally see my boy. Making out with another girl. Wow. Just- ugh.
You come up to him and ask him for explanations but all he says is dumb stuff.
*Zach's pov*
Me and Y/n go to a nightclub to celebrate our engagement, I tell her to wait on one spot so I could get us some drinks.
I go to the bar and order me and Y/n a mojito, then a girl comes up to me and gets mine and my girlfriend's drink and sips it.
Girl: Hey, you alone here?
Zach: Actually, I'm with my fiancée here. She's waiting for me so get back to her with some drinks.
*the girl gets Zach's drink, holds it in an odd mode and gives it back to Zach.*
Girl: Oh come on, have some fun!
Zach: I will have some fun when I get back to my girl, I have to go now.
*Zach takes a sip from his drink and feels a bit dizzy.*
*Zach walks back to the girl at the bar*
Zach: Hey... you look good tho..
Girl: Aw thanks!
Zach leans in and the girl grabs his face and they kiss. Zach doesn't know what's happening because the girl put something in Zach's drink, so he kisses back thinking it was you.
Zach's POV.
As I took a sip of the drink I felt kinda dizzy, then everything blacked out. I just remember seeing Y/n slapping me while crying. What did I do wrong?
To be continued...