<human>: Update 1: Just wanted to thank everyone for your responses! There was no way for anyone to be right here. Last night I stayed with a friend so I could just get out of the house. It seemed to help a lot. I'm still feeling a lot of guilt and all I can see is the two of them together. I also got a Facebook message from my friend's boyfriend. He said that both she and I have broken his trust... So I'm guessing he was not okay with it.
That's really all I have for the moment. After work today I'll talk to my fiancé about premarital counseling. Again, thank you all for your responses!

A little backstory, fiancé and I have known each other since we were about 13 years old. We've talked about threesomes before, and of course threesomes always sound good in theory. We've been together about 2.5 years and have been engaged since probably about mid-April.

Anyway, long post ahead, in advance, thank you for your responses.

My friend and I had gone to a concert last night, since she was driving I got completely trashed. My friend is openly bisexual and drunk me told my friend that I wouldn't mind my first threesome being with her and my fiancé. So, of course, those two are sober and agree to it. Friend proceeds to drink and fiance stays sober. Most of this consisted of my friend and myself fooling around, but you can kind of tell she wanted my fiancé.. So I let it happen.

I have never regretted something so much in my life. To watch the man you love just fucking drill another woman is heartbreaking to say the least. He did his best to maintain eyecontact wjth me while he was doing it, didn't always succeed. 

I feel like a fool. It was my idea, so why am I so upset? I feel like I have no right. So I guess, reddit, I'm just asking for some advice on how to cope with my poor drunk choices.

Can you condense the text into three sentences or less?
<bot>: Got drunk, asked my bisexual friend to have a threesome with fiancé and myself. Got hurt seeing him fuck her.