I just went back and read your first post and may back down from some of what I just suggested. Is your GF actively engaged in an affair? You mentioned some flirty messages with a few different OM's but I'm not clear on if that's still ongoing. If so then sometimes it's best to go as dark as possible. Basically do nothing for them and have nothing to do with them. Otherwise you are just feeding their cake-eating.
Me: 59 w/ S17, D23, D26 Current R: 4 years Previous M: 21 years; BD: 06-14-12; S: 09-10-12; D final: 03-17-14; XW:56