Moondance - there are some similarities in your story and our first experience. Our first experience in the LS was a threesome with a single male. It was also my wife's first experience with any other man besides me.
There was first time jitters but everything started off pretty well. After a while things were getting kind of awkward, I was not being excluded by my wife nor was he trying to "block" me out. Things were just not flowing as I had imagined, it was clear she wanted play with him. This was her first sexual experience besides me, and she was excited about it, so I stepped back and let her enjoy it. I took up a spot on the other bed and watched her have a great time. Admittedly, I was a bit dejected. After they were finished she came over to the bed I was on and made love to me. At this point, around 4 .m., we were both keyed up so we went across the street to a bar while our guest fell asleep. She explained to me that she was having a terrible time concentrating on two guys at once and thus having a hard time enjoying the experience. In fact she would prefer that we be with couples so we could each focus on our playmate. Again I was a bit dejected, but I dealt with it.
Flash forward a few weeks to our next experience, this time a couple, same room. I was on one bed with my partner, she on the other with hers. Not long into things I totally got it. I was distracted by her on the next bed, I was enjoying seeing her have a great time and having problems concentrating on the lady I was with.
Since then we have had other encounters. Even a solo for her, with the husband of one of our regular play couples, when I was unable to play due to surgery. During that same time period she had a date with the same single male as our first experience. Even though I could not play, I had 30+ staples still in me from surgery, I went along for her comfort level. I spent most of the time just enjoying watching her, but at one point I decided to go over and play with her breast while they played. At that point her entire outlook changed, she was way more interested in threesomes. We have both became far more relaxed and, as she says, capable of "multitasking".
The point of this long story? Don't put too much stock into your first encounter. You and your wife have never been in that situation before, add alcohol to the mix and it becomes more complicated. Keep communicating and don't expect real life to play out like the fantasies in your head. As you get more experienced in the life style you will both become more comfortable and capable of understanding fulfilling each others needs, as long as you keep communicating.