OP update... we played the gig last night WITHOUT our regular guitar player and everything went great. We had one friend come up to start the show with us on guitar, and we ripped through a bunch of Beatles songs and a few others. We played up the 50 yr. anniversary, and the crowd loved it. Then a couple guys from my singer's side-project came up and played 8 or 9 songs with my singer and drummer. I got to take a break while they finished the first set. I had no problem sitting out a few and saying hi to friends, etc. Also got to hear my band and my rig for the first time from the audience's perspective, which was cool. After the break, we finished the set as a 4-piece -- our 2nd rhythm guitar player/backing singer stepped up and played lead on a bunch of songs, and he did great. We even had a guy came up and play sax on a couple tunes with us -- I had never seen the guy before, and it was totally cool and out of left field. Overall, we had a blast and were very well received. The venue's manager came right up to us after the show with a big smile and said to plan on coming back soon. The best part is that the four of us looked at each other after we finished, and we all had smiles on our faces and only positive things to say to each other - no nitpicking at all. This is what it's all about for me.
Even before the show, we came to the consensus that our regular guitar player is out. If he would have played last night, I'm convinced that he'd be jealous and bitter that the other guys were stealing his spotlight. We don't need that kind of BS attitude, so he's long gone. I guess the moral of my story is that the band is about ALL of the people in it, not just one guy who thinks the world revolves around him. Thanks for the feedback everybody... keep on rockin'.
And with that, you have turned a negative into a positive.
Good job!