Have you or your partner asked your playmate to leave?

Me and my girlfriend are into MFM-threesome. And we had the discussion - what if we end up in the bed with the wrong person. Has anyone experienced that?
 
I have a few different times. Just be up front, but kind. I said something to the effect of "Babygirl, go and shower- freshen up and take a breather", then took the guy (once tranny) outside and explained that the vibe was off and if it felt different once she and I spoke Id be in touch ;)
 
We have a friend we enjoy mfm fun with, done it many times with him. Always at our home.
We're not swingers at all, we never go "looking" for fun. We like what we do with our friend.
One weekend out of town we were having a drink in the hotel bar, we do this whenever we're out of town. We get into a conversation with a guy at the bar. It's normal for us, we chat with couples, men, women, groups of people....never with sex play in mind. We had a couple of drinks with him, wife asked me if we might hit him up. I thought why not, we're out of town. He's friendly, good looking, we all hit it off pretty good. My just right drunk wife came right out and asked him if he'd like to join us, his jaw dropped and he looked at me. I nodded back. Another drink and we were really clicking. He asked his room or ours, we agreed on his. We got his room number, planned on 20 minutes to go to ours and freshen up. It was fuckin HOT for her and I anticipating what might happen. In our room were brushing teeth, washing up. She asked if I really wanted to do thus, we both said yes. She says, we have 15 minutes should we have sex first? We didn't.
Up to his room, I was scared, he opened the door, he was good looking. They hugged then started to make out, wife loves that. It was easy going, he told her to get undressed, she quickly did, he got naked, more kissing. He laid on his back, dick full hard. He told her to suck his dick. His attitude wasn't right for us. She did play with him and it was hot, he flipped her over and started oral on her, she was way into it. He suddenly stopped, told her to get on her hands and knees, and started to fuck her hard. I wasn't into what was happening, she went with it till he told her to flip over. She told him it wasn't working and wanted to leave.
Was VERY awkward but she put her dress on, underwear in her hands, grabbed her shoes and we left. She was mad telling my she didn't like how demanding he was, I agreed. Was a huge buzz kill.