My wife wants a girlfriend

I dont know if this is the correct forum for this but I have been searching around to be able to talk to someone, so here goes...my wife and I have been married for 9 years. Recently my daughter has a new best friend with a single mom. I always got a, for lack of a better phrase, "lesbian vibe" from the mother, turns out I was right. Over the course of the last month she had started to overtly hit on my wife which culminated a few weeks ago with a kiss. My wife immediately told me about the kiss and said it would never happen again. I believed her and we were fine. The following weekend approached and our friend came over again. We were having a great night until everybody started to get a little drunk and then the friend said to me, I really want to kiss your wife again. When my wife cam back outside I told her what was said and apparently she already knew because they had spoken about it earlier. I immediately said i wasnt ok with it, long story short they beat me down with reasons why it would be ok...it wont affect my feelings towards you, it wont affect our marriage, i still love you, etc. So I relent but say I'm only ok if I am there and not in a pervy kind of way, just to be there. They agreed. Almost immediately I regretted my decision so I told my wife the next day and she got angry that I was flip flopping but she maintained her stance that if it came down to it she would always side with me. The following weekend, things were following the same pattern and I knew I was being set up. So when they were both drunk enough they told me again and I said if I can be involved its ok with me. Our friend wants no parts of me being involved and my wife doesnt mind if i'm involved but would also be ok if i wasnt. All of which is not ok with me. So I stood firm and then they went off and made out with each other anyway. I then threw down the ultimatum of her or me, I know not smart. My wife said if its gotta be like that then she picks her. I am devasted by this, all I wanted to do from the start is make her happy and by doing so, I fear I have screwed myself. My main problem here is that when they both try to use the arguement that it's only a little time each week they get together and I still get her all the rest of the time, it isnt really true. They spend all night every night texting each other, and not sexting, just texting so now I dont have her attention at all. I am really trying to decide between leaving or trying to find a happy medium. Problem is, I feel like I have already been the one to make all of the concessions but nobody else is willing to concede anything? I am so confused and I dont know what to do. I have 2 children that I desperately do not want to leave.

I'm sorry your wife has decided to cheat on you. She is going to do what she wants to do regardless of your feelings. She has made that clear. She will cheat and she will cheat right in front of you. She isn't even going to bother hiding it. You don't WANT to leave yes, but its not up to you any more. Your wife has decided to end the relationship. Get a divorce and get a girlfriend of your own. Your wife has no respect for you, your children or your marriage. Do what is best for you and for your children and get away from your cheating spouse.

Part of being a parent is setting a good example for your kids, and kids are not dumb. They will figure out what's going on. Home should be a safe place where you can trust the people you love. When they see you letting this slide, it's going to mess up their lives too(present and future). It has to end, whether she ends it or you file for divorce. If she values your family, she will stop and go to counseling with you WITHOUT HESITATION.