Thanks all for your input.
I'll give you all a bit better background on their fiends dynamics then reply to you all. The friends are all from the same small (backyeard... in my eyes) town and they have all moved to a bigger town that we are in. The town is that small that Guy No.1 (as mentioned in my first posting) has slept with my girl, her best friend (Girl X) and is best mates with Girl X's boyfriend. Stay with me here... Guy 2 is a cousin of Girl Y's (another 'best friend) husband, Guy 2 has slept with half of their group. So it's damn hard for me to say "Don't have contact with these people" when, within their group, they have all literlly slept with each other and they don't have a problem with it - I see this a small town sydrome, but I'm not from there and not immune to this syndrome, it's killing me! And just to add salt to my wounds, all her friends think I'm a freak the way I respond because they don't understand that this is not the way things are done outside of your group of friends.
Anyway, now that I have the Jerry Springer explaination out of the way, I hope that answers your advice, HaloDestroyer, because the contact is always going to be there.
Melrich, we don't live in the small town so it is really quite possible not to see them (or have minimal contact). You mention the word trust, I have to say that it plays on my mind regarding 'trust' when your sitting there accross the table from the guy the had a one night stand with while with her husband!! Oh, just on a side topic - Guy 2 and my girl were both in the bridal party for Girl Y's wedding - That night I went through hell, and plenty of trips to the bathroom to be physically sick. You have to earn trust, and honestly, credibility is not one of her strong points.
friscodj, you ask the hardest questions of all and all I can say (sappy love moment coming up... brace yourselves) I've fallen for this girl... HARD!
This is why I want to talk about this, I don't want to separate, but I can't be like the others she hangs around because this is simply not the way I was brought up and I don't think I have go through this. Anymore comments would be appreciated.