My (28F) friend sent me a snapchat of my fiancé (30M) at the bar with another woman.

My fiancé Tim and I have been together (renting) for four years. We have a wedding date set and planned for next year. He has been so supportive and engaged in planning and everyday tells me how much I mean to him. We just booked a week long vacation after two weeks of getting our work schedules figured out.
He called me from work saying some some friends surprised him and they're going out. No worries babe have fun. He did not extend an invitation which I didn't think anything of, but I don't feel well so I stayed home. I texted him a little bit ago saying I'm going to bed, didn't hear back, but again it is a nonissue.
I woke up to my friend Gwen calling me. She told me to check my snapchat, which I did.
She sent me a video of him and a girl wrapped all over each other. They were laughing and he was touching her face and playing with her hair. I'm crushed. My chest feels hollow. I want to scream and cry and throw things but I'm sitting here on my bed with no idea what to do. Gwen left the bar and said she is coming over which I'm so grateful for. And it was at a bar I have been wanting to go to for a long time. Whatever that means anymore.
What do I do? I'm so confused.
TL;DR: friend sent me a video of my fiancé at the bar with another woman.


Source.